-Experimental 0.63.148743
When prone and using a scope, the view is obstructed by the vest and/or the backpack.
Crouching or standing don't have any issue.
I only tested with AKM + PSO-1, UK Assault Vest and/or Assault Backpack
When using the secondary sight (scroll down) there's no issue.
Without the vest and backpack, still no issue