All of the syntax/keyword highlighting, autocompletion and pretty much everything will fail if a user inserts a syntax error into the QML file e.g. changing "id: title" to "id: title:". The only way to get things back working is to make the QML file error free.

So far this has only been reproduced on my machine, but other macOS machines should be checked.

Screen Recording 2025-01-23 at 14.23.42.mov