On my machine it seems to land where I positioned it last time, the size seems always the same.
They once listed the issue as known, I can't find it now. 😒
This is what I mean by random size and position.
Looks like the behavior for you is quite different, with my 4K screens the size of the snip on the screen is always the same, but the file size apparently is not, and cannot be pasted unless I take a snip of a very small area of the screen. 😎
In the last 2 days they had so many problems on the platform, pictures lost, or cannot be pasted.
They are still working on the problems.
This one pasted ok, just a small chunk of the previous shot. 🤣🤣