I've seen a really strange bug that happens whenever MCA villagers and hostile mobs are together -- the both go crazy, moving around at warp speed, often jumping several block ahead without any visible in between frames. I don't know if anyone else has seen it, and I don't know its no cause by conflicting with code from some other mod (MineFantasy? Damage Indicators? I don't know, but everything else I use except Bibliocraft and MCA is world-gen oriented). Anyway, its weird and hard to deal with -- and I only see it when the villager and the enemy are both present and usually fairly close together.

http://youtu.be/7OSJ4OPx7f0

I'm unable to reproduce this in MCA 3.5.4 or current development code. Give the new version a try when it is available and see if it works any better for you. If it doesn't open this issue back up.

Thanks, will do.