After gradle is used, the BlockStateFlatteningMap.java file is just two bytes in size and contains two empty lines. This causes errors where BlockStateFlatteningMap is used and causes a compilation error.
I'm not 100% sure on the cause of this, but it's been observed that allocating more memory to the decompiler can help fix the issue. Not much I can do about it otherwise sorry.
After gradle is used, the BlockStateFlatteningMap.java file is just two bytes in size and contains two empty lines. This causes errors where BlockStateFlatteningMap is used and causes a compilation error.