When I click View Diagram in my application, the User - Group relationship shows as 1..1, yet my relationships table tells me it's M..M, why is this?
Style of your diagram seems to be obsolete. Which Rollbase version you're using? I see correct cardinality - see below.
I just tested this on version 3.0.5. I checked the release notes and it seems there are no provided fix so far. Kindly verify.
I see no problems with version 3.2 (current code base)