Sorry guys, but seems this is a wee bit more complicated than I first - naïvely - thought
Now I'm not sure if it's worth it to release the mod just yet, because there's clearly something else besides the campaign files causing these crashes there, too. I did succeed in salvaging a botched save a couple of times by switching them, yes, but that doesn't work anymore!
But regardless, if you want to try this out yourselves you can always replace your campaign files with the ones below. Remember to back up your old files first though!
Campaign_LND.mis:
[Mission]
Title=Empty
MissionType=0
MissionDataType=1
Year=1939
Month=1
Day=1
Hour=12
Minute=0
Fog=0
FogRand=0
Clouds=0
CloudsRand=0
Precip=0
PrecipRand=0
WindHeading=0
WindSpeed=4.000000
WindRand=0
WeatherRndInterval=5
SeaType=0
Briefing=
Campaign_RND.mis:
[Mission]
Title=Empty
MissionType=0
MissionDataType=1
Year=1939
Month=1
Day=1
Hour=12
Minute=0
Fog=1
FogRand=1
Clouds=1
CloudsRand=1
Precip=1
PrecipRand=1
WindHeading=0
WindSpeed=4.000000
WindRand=1
WeatherRndInterval=4
SeaType=0
Briefing=
Campaign_SCR.mis:
[Mission]
Title=Empty
MissionType=0
MissionDataType=1
Year=1939
Month=1
Day=1
Hour=12
Minute=0
Fog=1
FogRand=1
Clouds=1
CloudsRand=1
Precip=1
PrecipRand=1
WindHeading=0
WindSpeed=4.000000
WindRand=1
WeatherRndInterval=4
SeaType=0
Briefing=
I'll investigate this further & keep you guys posted. S!