I am not sure if this can actually be considered a bug, but my character's Dexterity does not improve when using unarmed combat. In the skill info it states that it can be increased by using light weapons, but I am not sure if it really makes sense to be able to have a guy with 45 in Martial Arts, 24 in STR, 22 END and... 3 DEX.
Anyway, hope this helps, and mighty congratulations to the team. It's pretty amazing what you are creating.