I have Hamstring 30 and it doesn't slow the mobs in this room, like it used to before Update 76. I am using the .IMG file version from here: https://royals.ms/forum/threads/still-crashing-after-76-1.200777/ (no Windows 7 compatibility though) This issue probably isn't actually important but just letting y'all know. Maybe some other mobs/bosses that are meant to be hamstring-able are broken too (in particular, I haven't been Auf since the patch to check).
Can you try setting compatibility for windows 7 and report back? The compatibility switch is supposed to fix status effects (for mobs) not working, such as stun, freeze, etc.