Okay, fixed that, uploaded a new version. There was an error in how the normal map was being initialized, which older versions of GM didn’t seem to care about but .13 now errors on.
Sorry to bother you again, but I still get the error in the sample project. I deleted the old version of deffered chickens and imported the updated version. I get the same error.
Also Cartoon, Luminous and Shadow Chickens aren't included in the .yymps package anymore.
Huh, I wonder if this is a different problem than the one I found then. You can send me the project on discord or something you want me to take a deeper look.