he/she is using from his/her hands inside a building and possible either near another object or wall.

Here is the video proof (start the video at 04:45):

https://m.youtube.com/watch?v=fqPEoGdRGwQ

I also died once when I took a shotgun into my hands and then tried to made it into a sawed-off one. This time I was in the second floor of the corner pub, where there are 2 chairs and a white low table. And somewhere between the left chair and the table my character died, when it sawed the shotgun and droped it.

The game probably puts you inside the wall or object you're using and then you die. But I can not be sure.

I also died 2 days ago, when I climbed up a ladder at the Berezino lumber mill's school building. When I got up to the roof where the small square is, I died. I am not sure what happened there.

I'll post the steps to reproduce this really sometimes annoying glitch once I've done some testing. But the ladder executoner glitch you can fix by adding an animation that the character takes few steps forward when he/she gets up to the top.