I can confirm that this is happening with all magazines, at least for me.

I can acknowledge the validity of this. Has happened to me a few times, but only on -NewUI

I can understand the limit for 3pp, but it really makes 1pp frustrating.

Are you using launch parameters? If so, get rid of them.

Just drag the flare to the Vicinity zone of the Inventory. Or put it in your hands and throw it.

If it is a problem, I also get error message upon closing the game in any way.

This has happend to me about once or twice before, but since, took a break and came back to Experimental, I have not encounterd it agin. It probably has been fixed.

This happened to me all the time. But it stopped in .46, so I don't know if it was something I did or something in the update.
*Edit This was really annoying when it happened while zombies are attacking! Having to force quit while zombies are hitting me has made me loose characters.