I guess it's the same reason people weren't getting activation emails(I disabled activation to enable registrations).
I don't have access to this new server, so I can't take a look.
I mentioned the problem to jkbbwr, and he said he'll look into it.
But that was a while ago, so I'm guessing he might have forgotten...
Friendship is magic!
R.I.P. Tracy M. You will be missed.