[@netweb Keymaster 10 years, 4 months ago]

I’m pretty sure the “founder” setting won’t have anything to do with it 🙂

What I think has happened is when you first import your forums the users will be imported as user1, user2, user3, user4 etc, if you subsequently perform another import and you did not reset the forums, or delete delete the imported users then those same 4 previously imported users will remain and the import rather than overwriting these users will import those 4 users as imported_user1, imported_user2, imported_user3, imported_user4.

I suspect this is what has happened and hence the mismatched post to author relationships.