Thanks for the recordings! Would you be able to record one on Jam so that we get more specific dev information that may be useful to debug? Do you know if this also happening on different browsers?
I'll continue the conversation here in case it helps any other user having a similar issue. In the Jam recording, I can see that the rich text field shows up as a paragraph in the API, so this should tell us the problem is in the browser.
Have you seen this happen in different browsers? It could also be a plugin issue, if you have any, could you remove/deactivate them and see if it fixes it? If it does, you'll just have to re-add them one by one to get the culprit
We've investigated further, and this seems to be a Prismic bug. I've created a bug report and passed this on to our team. You can track our progress here: https://prismic.atlassian.net/browse/BT-217.
Thanks for your reporting, and if you need help with anything else, don't hesitate to reach out