I am sure this is a known issue. If you have anything in your hands, especially while crouched and you go to climb down a ladder you are flung to your death. I have taken many ladders without issue while having my hands free. The only time I have an issue is when I have something in my hands.

What floor were you on?

The mosin did fall to the ground later after equipping and unequipping the M4 when my hands were empty.

Can also be done with large melee weapons when you don't have inventory space for them. I tried with a Mosin and M4 and also a Wood Splitter Axe and a baseball bat. Uploaded pictures

Yep can do this. Sometimes can also see it try to split and end up with like a 27 and a 40 and a 30 when you have a previous stack that wasn't a full 30.

I enjoyed skydiving off the hospital ladder from the roof in Berezino when approached from a diaginal. It looked like I took a running jump off the roof when told to climb down ladder with rifle in hands but not in ready position.

My issue stems from finding a server I am liking and trying to get back to it and not remembering the name. Particularly since the respawn has not been working properly and you need to logout to respawn.