Does the Raven Queen's Sentinel Raven apply a bonus to passive Perception twice?

Question

The Raven Queen, an Unearthed Arcana warlock patron, grants a raven companion who assists you with Perception checks whilst perched on your shoulder.

While the raven is perched on your shoulder, you gain darkvision with a range of 30 feet and a bonus to your passive Wisdom (Perception) score and to Wisdom (Perception) checks. The bonus equals your Charisma modifier. While perched on your shoulder, the raven can't be targeted by any attack or other harmful effect; only you can cast spells on it; it can't take damage; and it is incapacitated.

This question arises when you need to calculate passive Perception. From PHB 175,

A passive check is a special kind of ability check that doesn't involve any die rolls. Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster.

Here's how to determine a character's total for a passive check:

10 + all modifiers that normally apply to the check

If the character has advantage on the check, add 5. For disadvantage, subtract 5. The game refers to a passive check total as a score.

For example, if a 1st-level character has a Wisdom of 15 and proficiency in Perception, he or she has a passive Wisdom (Perception) score of 14.

The rules on hiding in the "Dexterity" section below rely on passive checks, as do the exploration rules in chapter 8.

Since the raven boosts Perception and passive Perception, would the warlock's passive Perception be equal to 10+WIS+proficiency (if applicable)+CHA (bonus to perception)+CHA (bonus to passive perception)?

Answer 1

The Charisma Bonus probably only applies once; but the feature is worded poorly

This kind of interaction should be adjudicated by the DMG's rules for Combining Game Effects:

Different game features can affect a target at the same time. But when two or more game features have the same name, only the effects of one of them-the most potent one-apply while the durations of the effects overlap. For example, if a target is ignited by a fire elemental's Fire Form trait, the ongoing fire damage doesn't increase if the burning target is subjected to that trait again. Game features include spells, class features, feats, racial traits, monster abilities, and magic items. See the related rule in the 'Combining Magical Effects' section of chapter 10 in the Player's Handbook.

—Combining Game Effects, Dungeon Master's Guide, pg. 252

So one way to interpret this is that the Warlock is getting one bonus, applied twice:

Wisdom(Perception)[Passive] = 
    10 
  + Wisdom 
  + Proficiency (Perception)
  + Charisma (Sentinel) 
  + Charisma (Sentinel)

However, because the Charisma bonus from the Raven Sentinel is being applied twice, we'd rule that only one of them applies. So of the two Charisma bonuses in that formula, one of them gets eliminated, and we only add the Charisma modifier once.

I do agree though that the way the feature is written is troublesome for this interpretation. You could get the [probably] intended outcome by instead writing something like:

While the raven is perched on your shoulder, you gain darkvision with a range of 30 feet and a bonus to your Wisdom (Perception) checks. The bonus equals your Charisma modifier. [...]

I don't believe any DM worth their salt would interpret a phrasing like this to imply this bonus wouldn't apply to the passive score. So the decision to double-reference Perception—to say "applies to Passive Wisdom(Perception) and to Wisdom(Perception) checks"—implies one of two things:

• The designers were worried DMs would not interpret the bonus as applying to Passive checks, and wanted to make that clear, OR
• The designers intended to confer a "super bonus" to Passive Checks above-and-beyond what is applied to active checks.

But if this latter interpretation were the intended interpretation, they ought to have opted for a different phrasing:

While the raven is perched on your shoulder, you gain darkvision with a range of 30 feet and a bonus to your Wisdom (Perception) checks. The bonus equals your Charisma modifier. This bonus is doubled when applied to your Passive Wisdom(Perception) score. [...]

This would leave no ambiguity about how to apply the bonus.

So in total, my best reading of the feature is that it only applies once, and that if the 5e game designers intend[-ed] to fully flesh out this patron for a proper release in a sourcebook, they would do well to revise the wording to avoid potential confusion, regardless of how they intend the feature to function.