A while back we got this bug fixed:
But it seems to be back. I can't type Japanese in comments without this problem anymore. Could you please fix it again?
This appears to be back, at least for the past few months (as of 2021-05-20). Running Firefox 78.10.1 esr at the moment, I've seen it on older esr versions too.
Possibly due to behavior of the IME, I often find that, as I'm typing in Japanese, hitting ENTER to confirm the conversion candidate is caught somehow by the browser instead, and my comment is committed even though I'm not done writing. This is most annoying. Thankfully, I can still edit my comment (since it's within the 5-minute window), but it is frustrating and a UI failure.
If we could disable ENTER from committing comments at all, that would be most welcome.