KaleunMarco, have them look in the whole Save folder (C:\Users \UserName \Documents \SH4 \cfg \SaveGames), and find the two latest numbered folders under there, and alter the CareerTrack.upc file to get a different "PlayerCurrentObjectives=IDxxx" number of a valid "local" assignment. Use Flotillas & PatrolObjectives to find a known-good mission ID that is NOT in the CareerTrack file.
For an actual "fix", the ...cfg \UserPLayerContextGE \ Flotillas.upc file might have to be edited, as well as the UPCDataGE \UPCCampaignData version (I don't remember that now). 1Patriotofmany is "falling through" to the default German Career mission ID set. Either missing an assignment for the time period (like you found in FotRSU), or a bad ObjectiveCode - AllMatch between Flotillas and PatrolObjectives, or maybe an empty AllMatch pool of missions...
