The sights are not lined up. To fix this, edit weaponheavyshotgun.meta in
mods\update\update.rpf\dlc_patch\mplts\common\data\ai

Search "FirstPersonScopeOffset" and replace the 2 rows with this

<FirstPersonScopeOffset x="0.000000" y="0.105000" z="0.004000" />
...
<FirstPersonScopeRotationOffset x="0.220000" y="0.000000" z="0.000000" />