An argument against the trick
Ultimately, Magic of Incarnum is ambiguous here. Below I address three possibilities for how the wording could be read.
A subtle distinction?
There is—arguably—a subtle distinction among incarnum feats. It is not remotely explicit in the rules, and the wording doesn’t even change from what I’m arguing is one kind vs. the other kind.
Thus, this is, unfortunately, somewhat motivated reasoning: the trick shouldn’t work, so how can the words written prevent it? A more-neutral analysis might find these conclusions dubious, and argue there is no such distinction. However, even a more-neutral analysis, that pays no mind to how things “should” be, finds at least two possibilities for that lack-of-distinction. I’ll discuss that at the end of the answer, because I find that thinking about this possible distinction elucidates what’s left if you decide it doesn’t actually exist.
The distinction is also potentially useful for ruling things at your own table, though frankly that is an entirely separate question and has much more to do with the power level of things at your table.
Anyway, what I’m getting at:
Azure Enmity [Incarnum]
Benefit: Once per day, you can invest essentia into this feat. You gain an insight bonus equal to the invested essentia on Bluff, Listen, Sense Motive, Spot, and Survival checks made against all of your favored enemies. You also gain an insight bonus equal to the invested essentia on weapon damage rolls against such creatures. Once the amount of essentia invested is chosen, it cannot be altered and remains invested for 24 hours.
Azure Talent [Incarnum]
Benefit: Once per day, you can invest essentia into this feat. You gain bonus power points equal to twice the invested essentia. Once the amount of essentia invested is chosen, it cannot be altered and remains invested for 24 hours.
(Magic of Incarnum, Feats listing, pg. 34)
Here we see the first two feats listed in Magic of Incarnum, both of which are incarnum feats. We see the common template used by all incarnum feats:
Once per day, you can invest essentia into this feat. You gain […] Once the amount of essentia invested is chosen, it cannot be altered and remains invested for 24 hours.
(Magic of Incarnum, common wording on all incarnum feats, pg. 34-41)
All of them start with the same 12 words, and end with the same 18-word sentence.
Where they change, however, starts with word 13. For Azure Enmity above, that’s “an insight bonus equal to […],” and Azure Talent says “bonus power points equal to […].” Most incarnum feats are like Azure Enmity: they just apply one or more bonuses to various rolls. Azure Talent, Azure Toughness, and Sapphire Smite are different because they also provide extra of a specific resource. (Sapphire Smite actually does both, applying a bonus and providing more of a resource.)
A “bonus” is a specific, defined thing in D&D 3.5e. It is specifically defined as a number you add to a dice roll. It can have a type (such as “insight” for the bonus provided by Azure Enmity), there are rules for how they do or don’t combine, and so on.
Despite the use of the word, “bonus power points” are definitively not a bonus. You do not add this number onto any roll. So despite the very similar wording, these two feats are doing things that are significantly different under the rules. A “bonus” is a constant thing, that applies continuously and can change on the fly. “Bonus power points” are not, they are something you get once and just have until you spend them or refresh your power points:
Just as a high Intelligence score grants bonus spells to a wizard and a high Wisdom score grants bonus spells to a cleric, a character who manifests powers (psions, psychic warriors, and wilders) gains bonus power points according to his key ability score.
(Expanded Psionics Handbook, pg. 18)
Like spell slots, this is a thing that happens upon refreshing power points. And just like bonus spell slots, bonus power points are not gained or lost if your ability score (or manifester level, for that matter) changes after that. (Negative levels do cause the loss of power points, but that effect is spelled out as part of the effects of a negative level, just as it is for spell slots.)
Thus, it makes complete sense for the value of a bonus to change throughout the day. One’s number of bonus power points does not—when you refresh power points, you get bonus power points, and that’s the end of that. Bonus power points aren’t a stat like a bonus is; they’re a quantity of resources that you’ve been given.
In other words, Azure Enmity applies an ongoing effect. Azure Talent describes a one-time event, triggered by the act of investing in the feat. Azure Toughness is similar. Sapphire Smite also describes such a one-time event, as well as describing an ongoing effect.
So how does this one-time event interact with Psycarnum Infusion?
one of your […] incarnum receptacles is treated as if it had essentia invested in it equal to its maximum essentia capacity
(Magic of Incarnum, Psycarnum Infusion feat description, pg. 40)
The way I read this is, unlike most incarnum receptacles, including most incarnum feats, Azure Talent doesn’t have any benefit for merely having essentia invested in it, but instead gives you a one-time benefit for performing the actual act of investing.
Since Psycarnum Infusion doesn’t actually invest essentia—it treats the receptacle as if it had already had essentia invested in it—you don’t get any particular benefit because there isn’t any particular benefit to having essentia in Azure Talent. There’s only a benefit from the actual process of performing the investing.
In a very real way, the “had invested” here is technically correct: it is describing a past action that we’re now pretending happened. If the investment happened in the past, so did the reward of power points. You don’t continue to gain power points just for having the essentia sit there.
The crown chakra is another complication. Azure Talent has a second paragraph that reads
If you have the ability to bind a soulmeld to your crown chakra (even if you don’t have one currently bound), you gain an additional 2 bonus power points as long as at least 1 point of essentia is invested in this feat.
(Magic of Incarnum, Azure Talent feat description, pg. 34)
Like the first paragraph, this describes an event (“you gain an additional 2 bonus power points”) that occurs when certain conditions are met (“If you have the ability to bind a soulmeld to your crown chakra,” “as long as at least 1 point of essentia is invested in this feat.”). Unlike the first paragraph, it does not indicate any particular timing for this event.
This can be read in two different ways:
The described event takes place as soon as the conditions are met.
The description is an extension of the prior paragraph, and the second event happens when the first event happens if the conditions are met at that time.
In case 2, since the event described by the first paragraph doesn’t take place, you never gain additional bonus power points.
In case 1, however, if you use Psycarnum Infusion while having access to the crown chakra, and cause Azure Talent to be treated as if it had (at least 1 point of) essentia investied in it, the event occurs and you gain an additional 2 bonus power points. Thus, this probably¹ works.
Anyway, these two scenarios are, in most circumstances, equivalent, as one cannot usually have essentia in the feat without investing it. As such, the rules text itself does not specify which case it is, and so both 1 and 2 are valid readings. Thus, this necessarily must be left up to a DM ruling.
- There could be arguments about the word “additional” with respect to the nothing you’ve otherwise gotten, or about the feat “stacking” with itself—but these are necessarily pretty speculative, because “additional” doesn’t have a hard-and-fast technical definition here, nor is stacking really defined for bonus power points (and as an event, Azure Talent reads like an instantaneous effect anyway).
“You’re making that up”
Maybe. The distinction between a bonus and bonus power points is definitely real, but it’s certainly true that the wording of Azure Talent doesn’t make even the slightest of nods towards that distinction.
So where would that leave us? Azure Enmity and Azure Talent would have to be treated the same. So what happens when you use Psycarnum Infusion on them?
Much like the debate about the crown chakra above, the wording is ambiguous. “Once per day, you can invest essentia into this feat. You gain […],” could very easily still be talking about a triggered event: investing in the feat triggers the gaining of the benefit. Psycarnum Infusion wouldn’t work with that.
The counterargument is that Psycarnum Infusion explicitly lists incarnum feats as a type of incarnum receptacle you can use it with. And indeed, you certainly can use it with them under this reading—but it would do nothing. The feat certainly “should” have some meaningful use with each of the things it explicitly suggests using it with—but “should” is a dangerous word to use if you want to be totally objective about things. Nothing in Psycarnum Infusion guarantees that using it with any given incarnum receptacle will necessarily cause anything to happen. There is not a contradiction of the rules here, just a contradiction of our expectations. Which the perpetual power point trick is also.