I really appreciate all the info. It's invaluable in order to more easily solve problems like these. For sure, I understand that it's worrying, so it's great that you're using version control! I just released a game and work full-time, so I can't promise exactly when I'll get this one fixed, but I promise I'll be as quick as I possibly can. I never used LTS myself which might be the main culprit behind this in itself. I think I'll get that version you're using and see if I can find the issue. And yes, if you wouldn't mind, I'd like to look at the yy files as well. Please drop me a mail at prote1337@gmail.com. :)
I just released a new version, but the fix for this isn't included unfortunately. I tested GM Link with your aseprite file and the newest LTS version of GM and everything worked perfectly, so I wasn't able to reproduce it this time around. Hopefully we can come close to the root cause soon so it can be smashed. I'll continue pondering about what could be causing it.