Im sitting here getting shot up cause i cant get vatts to respond to the button command.

i found that if u use the aim trigger before u hit vatts trigger it works for me kind of annoying but it works

encounter same thing back in the gosttown quest also.

I have encountered this bug like twice but i was a pretty good aim using the iron sights so it did not bug me.

I've encountered this bug sometimes, too. I've found the trick is (if it's active) to leave killcam deaths on, until you get one yourself to activate. That should reset VATs. Another thing I've tried that works sometimes is if you're sneaking and it's not working, stand up, and then get into sneak position again. Try targeting your companions to see if it's active again. Hope this helps.

save plenty and reload when things are behaving buggy.

Yeah, I've had this happen quite a few times too. Usually if I fire a shot VATS will start responding.