Do objects created by prestidigitation last forever? And are they immune to dispel magic?

Question

The duration of the spell does not indicate the duration of the prestidigitation effects.It instead indicates how long you can create magical effects with a single casting.

Once cast, a prestidigitation spell enables you to perform simple magical effects for 1 hour.

The only mention of effects fading is at the very end.

Any actual change to an object (beyond just moving, cleaning, or soiling it) persists only 1 hour.

According to this, if you have 1 minute left on your prestidigitation spell, you can change the color of an object and it will stayed colored for an entire hour, even after prestidigitation spell ends.

So putting all this together, since there is no explicit duration specified for the fragile objects created by prestidigitation, do these objects last forever? And are they instantaneous duration or permanent duration? (The former is not dispellable while the latter is)

Answer 1

The objects vanish when the time is up

The rules for spellcasting state under Duration:

Timed Durations

Many durations are measured in rounds, minutes, hours, or some other increment. When the time is up, the magic goes away and the spell ends.

Since Prestidigitation has a timed duration of 1 hour, the objects are sustained by its magic and will go away. This would be different if the duration were Instantaneuous ("The spell energy comes and goes the instant the spell is cast, though the consequences might be long-lasting.")

For the same reason, they are not immune to dispel magic.

Some effects can survive the duration of the spell, as the spell explicitly says so:

It can color, clean, or soil items in a 1-foot cube each round. It can chill, warm, or flavor 1 pound of nonliving material. (...) Any actual change to an object (beyond just moving, cleaning, or soiling it) persists only 1 hour.

These effects are not creating an object, they are changing an existing object and in these cases the specific rule overrules the general duration rule.

As per the spell description, moving, cleaning or soiling the object will leave a permanent change. Coloring, chilling, warming or flavoring will last for one hour. So, if you cast prestidigitation and color an object 5 minutes before the end of the spell's duration, this coloring will vanish one hour later, or 55 minutes after the spell ended.