I acquired the Lycanthrope mutation and suddenly couldn't attack with any consistency. Over the course of a thirty-second battle, my character was only able to swing about three times, randomly. Mostly he did not swing as I was clicking furiously on enemies. Movement was fine. Enemies also mostly ignored me.
The few successes I had swinging almost felt like I had a very specific tiny spot on enemies that allowed me to attack; although, that's just a guess. The skill description says nothing about altering combat functions (such as needing to unequip all weapons to fight), so I don't THINK I'm misunderstanding the effects of the Lycanthrope mutation.
Also, the character and lycanthrope model will flash on and off during the beginning of movement. That's certainly a glitch of some kind.