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.

Maybe try less condescension.
A group of people spending the entire day together are going to talk and have interactions all day long. It's weird that these discussions would happen exclusively (or even primarily) at night.
When I go to work, I don't just put my head down and do 8 hours of work without talking to anyone. I'm frequently talking to the people around me about what I'm doing or what they're doing or what we're doing together. Everyone that I've ever worked with does this. We're social animals - not machines. Your suggestion that people should just have all of their conversations at night
detracts from immersion - it's not how people behave.
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?

If you can't see how, that seems like your problem. Of course they don't need to return to camp every time they short rest. Of course Larian can figure out how to have Gale and his mirror image not collide with objects. Just because you can't do it, doesn't mean it can't be done.
From a spell slot perspective, I am perfectly willing to assume that he's using Minor Illusion or is using magic in a way that isn't perfectly encapsulated in an existing cantrip. He's playing with a simple illusion, not disintegrating someone.
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
I'm fine with that, too, if they can make the transitions between them convincing. I still think they should happen at various times throughout the day.