I also have this problem. It only occurs while standing or walking, not while running. The fence direction doesn't matter. The character needs to hold a weapon which is also held in the second hand while idle (the weapon animation also used in the video posted by Quereilla).
I also found another report of the same bug here: https://steamcommunity.com/app/108600/discussions/0/3198117849827030424/
Like the reporter in the link I also use Debian Linux (testing instead of unstable).
edit: version 41.65 without mods
