If I don't End Day right then,
I never did ...
I never trigger Gale's Mirror Image dialogue.
I allways had. O_o
And concidering other comemtaries, im not the only one. O_o
I barely did anything, might be full health with full spell slots, but game makes me End Day or miss dialogue.
See and that is the problem ...
Game provides you mechanics, you refuse to use them, game even tells you that you SHOULD use them, you ignore that either ... and then you dont like the outcome. :-/
In fact whole game (maybe except two, three fights) can be done without spending single spellslot.
You call that "good roleplay" ... and all you see is your HP and number of used spellslosts ...
Your character just woke up after being abducked by aliens, survived flyting through hell, escaped that ship and multiple times fight bunch of brain-tentacle-claw beasts ...
If that is not enough to demand a little rest, i really dont know what is.

Consequentially, I don't have a ton of examples, because I don't get to see them. One, off the top of my head is Gale's looking at his own mirror image thing. There's no reason that this needs to happen at night.
Next time i shall answer for this argument, i start quoting myself ...
But lets repeat.

There is reason for this to happens at night, during day your characters are solving most pressing matters, at evening (or night if you wish) they have free time, therefore there is enought space for reading, thinking, playing with githyanki toys, and talking.
Its just that word people uses so often around here to justify their own opinions ... its imersion.

It probably shouldn't happen while you're in transit, but it could totally come up during a short rest.
I dont quite see how ...
Either you would need to return to camp for every short rest ... wich sounds both ridiculous and anoying.
Or you would risk stucking gale, or his mirror image in other obejcts ...
Also if you see it from purely RP perspective, it also does not make sence ... just imagine, you just finished fighting the goblins, decide to rest ... and sudently Gale instead of resting decide to spend his spellslot to summon his own mirror image so he can admire himself?

I assume there are other scenes like this. Why make them all only come up only during long rests, where they are competing for space and so you end up losing out on story moments?
Dunno, maybe ... possibly ... probably ...
But that could be also resolved by simply allowing players to have multiple conversations in row instead of only the last one. O_o