Just noticed that in one of the latest releases (either 2.5 or one of the last preview releases), Revit decals with a cutout mask don’t render anymore.
ps: while you’re fixing that, any chance you can enable self-illumination for decals in Revit 
Please see the existing thread: Version 2.5 - Revit Decal Cutouts Not Working
It has been fixed in the meantime and will be part of an upcoming hotfix.
BTW: Self illumination decals are working already now
Sorry should have checked the forum before posting!
I tested self illuminating decals in 2.4 but they were not working yet. Was this added in 2.5?
Yes, they’ve been added for 2.5!