The suffix is indeed generated by OCUM and passed on to the WFA workflow.
From the OCUM online help of the SnapVault protection dialogue:
[...]
A suffix between 001 and 999 is appended to the secondary name when the relationship is created, replacing the nnn that displays in the preview text, with 001 being assigned first, 002 assigned second, and so on.
[...]
The idea is to circumvent duplicate names that would cause the workflow to fail as mostly the name is dynamically created based on other variables that can be identicale for different relationships.
The intention is correct, but I can understand that people may not like that behavior.
Unfortunataly there is no build-in way to remove it.
regards, Niels