Thanks for the screenshots. A 400 error when submitting a comment usually means something about the request is being rejected, so we will need a bit more info to reproduce it.

A few quick questions:

1) What is the exact URL of the page where this happens?

2) Are you logged in when you try to comment, or are you commenting as a guest?

3) Does it happen on every post or only that one?

4) What browser and device are you using?

If you can share the approximate time it happened and the email address you used to comment, our support team can also look up the request on our side.

Thanks again for flagging this. Once we have an update, you will get notified here.