If you are in the low crouch position (special stance) and pull out the map and close the map again your character will fully stand up and then goes back to normal crouch position. The character needs to stay in the same low crouch position just like when you use the map while sitting or in prone position.
- Legacy ID
go in low crouch position and open and close the map.
Indeed, I can confirm this happened to me multiple times while trying to stay covered in a watch tower. One of the many stance-related bugs that could easily be fatal for obvious reasons!
The character appears to go prone instantly as soon as the map is closed, then he automatically stands up and goes back to middle crouch.
This was already reported in #2028, but without specifically mentioning the stance problem.