As the title says, the LRPS is not seated properly when attached to the M320 LRR.

Edit: After some research, I found out that this issue depends on the weapons. The following weapons have issues with nearly all scopes:

M14 EBR
GM6 Lynx (all variants)
M320 (all variants)
Mk200
TRG-20 (all variants)
Katiba (all variants)

The other weapons should be fine. {F24359} {F24360} {F24361}