The corrections feature is pretty much for show now and serves no real purpose. For the most part, it just suggests errors, but doesn’t give me the correct answer. The other most common error is that it can’t differentiate between old British English, so why is American English the correct way to spell it?Is colour the wrong word! This is important because I hate having red marks. But I can’t turn that option off.
Is your system language set to American English?
No, the system language is Chinese. Following your hints, I tried different programs. “British English”, “U.S. English” and “Auto”. The result is that if I switch to British I get an American error. That means that actually obsidian calls the system’s spelling correction, but that’s a conflict in itself, which seems to have become an unsolvable problem.