Shotgun:

ERROR] workshop/lua/weapons/fas2_base_shotgun/shared.lua:291: attempt to call method 'RestartGesture' (a nil value)
1. ShotgunThink - workshop/lua/weapons/fas2_base_shotgun/shared.lua:291
2. unknown - workshop/lua/weapons/fas2_base/shared.lua:1041

To fix the error you need to extract the contents of the FA:S SWEPS base and go into the base shotguns folder. Then edit the lua in there. Search for RestartGesture and delete it along with the entire line its in. Save. Done. If you have a server you need to import the newly extracted FA:S SWEPS base into the add-ons folder of your server.