Offline payment went wrong

Something went wrong with a registration this morning: person registered for a course, chose etransfer. However, when they submitted it, EB is supposed to mark that registration as pending, and send the offline payment email. Today, the system marked the registration as paid & sent the full registration confirmed email. It has never done that before. 

The last time someone chose etransfer as a payment option was May 13, and everything went fine with that one: it was marked as pending and sent the offline payment email. I have not updated/changed anything with EB since then. There is nothing different about the event that went wrong today and the many events that went right previously. 

Any idea what happened? Superuser access is difficult and I'm not super upset by this as long as it looks to be a one-off, just wondering how I can check to make sure it won't happen again.
Edited to add: I think I was actually editing the event - I was changing the name of it to reflect that there was one spot left - at the same time as they were registering. Could this be what caused it to get messed up?

Thanks,
Melissa

Attached images: 
1. EB record showing the etransfer marked as paid, instantly after registration completed. 
2. Email log showing what email was sent to registrant (note time stamp)
3. The email list showing the 2 different titles of emails
4. What it should have sent when etransfer chosen: user_email_body_offline
5. What it actually sent in this case: user_email_body