Me and a mate started a group iron together, ingame it shows correctly as a 2 man group but on the high scores it shows as a 3 man and there is a "open slot" for the third person
Is there anyway to fix this out end of is this somethjng a JMOD has to handle manually?
Submit a Bug Report from inside the game.
If several weeks go by and it hasn't been fixed, try reddit to get the name of the JMod handling the issue. A year ago it was Mod Light but I don't know if this is still the case.