Hey DeEz,
do you mean that they can't be selected in the GM Camapaign settings window? Or you select them there and when starting the campaign, they do not work? Can you link me one or two of those add-ons, so I can recreate the issue here?
Sincerely,
Kevin
They can be selected, but the selection is never saved to the campaign metadata.
To reproduce: create an Adventure (not Add-on) mod that inherits from GM. Make a new campaign and in the campaign metadata, select said Adventure mod then add an addon that only targets GM (example:
http://steamcommunity.com/sharedfiles/filedetails/?id=1265938852).
I managed to fix this by manually editing mods that only targeted GM to target both Story and GM. They then saved correctly in the campaign metadata.