This is probably not a bug as such, but a very troublesome feature. I was trying to Bulk Invite From File, and got a nasty shock when I uploaded the file and it immediately sent the email to 30 people. I guess I assumed there would be a step where it shows that the file uploaded and then offered a button to actually do the send. So I uploaded the file–intending just to familiarize myself with the process–and embarrassed myself by sending invitations before a key piece was ready. I had to send a manual followup explaining the glitch.
I really think that Bulk Invite button needs a confirmation or other speed bump, because the consequences are fairly drastic.