NBT Tags causing workspace to stop 'compiling properly.'

I've been attempting to add an NBT tag to a plant using a procedure and I've found that everytime I introduce one the workspace will fail to compile and I cannot launch the mod in the client. I've since tried using a simple 'Set NBT tag,' on a block and this has also prevented the client launching. The issue isn't because I haven't given my blocks tile entities, I've done this. I'm using 2025.1 and a fabric plugin. Any help greatly appreciated!