Something caused posting an answer to fail for me (the web interface just sat there, the "Save Post" button disabled, but nothing further happened). To recover, I copied the text of the answer into a separate window, force-reloaded the page with the question, and then proceeded to select the text in the separate window, middle click in the answer body field to paste it (as is a typical workflow in X11), and again clicked "Save Post".
The result was an error message that the answer body text was too short, and needed to be at a minimum 30 characters.
Except [the answer](https://meta.codidact.com/posts/283073#answer-283073) was well over 2000 characters long, so the error message was clearly in error in that case; as further evidenced by the fact that simply re-clicking "Save Post" on the reloaded page allowed the answer to be posted.
It might be related that the preview also didn't update to reflect the pasted content. I have seen that before, in that I have to do something further with the body text for the preview to update, but I haven't before got an error back when trying to save a post in that situation.