Hello,
OK then I would check 2 different things:
1) First: transaction SMOEAC in CRM: maybe someone set a filter for replication object BUPA_MAIN... which would result in a Bdoc being generated, but with green status because it would be sent to nowhere.
2) Second: transaction SMW01, because even if the Bdoc is green sometimes when you click the display error button, and go to the detail screen, you get some error messages that are displayed in the log.
Regards,
Nicolas.