The problem with LLMs for translation is when they refuse to do so if the topic being translated isn’t following their policies, even if the context shows it’s fine here.
It can be as simple as discuss one’s own religion
It can be as simple as discuss one’s own religion
I also have a few heuristics (e.g. "I can't translate" in many different languages) to detect if it deviates from that.
It works pretty well.