I have a weapon with vampiric regeneration: 1 but when I hit only every so often does any damage get turned to life. I assumed that 1 of ever damage I dealt would be sent back to me, but tht is not the case.

At any rate I figured this was a bug of some sort.

It's more a NWN bug instead of a server bug, I think it usually does the regen on the first hit if you hit every round or so.

Yes. It's not a very powerful ability. I've noticed that you get life maybe every 3-5 hits.

This is an engine-level issue pointed out in an NWNWiki article: http://www.nwnwiki.org/Vampiric_regeneration

Nothing we can do about it.