"This field editor is broken" error

I’m trying to populate a rich-text field from an existing database, using the contentful_converter gem to translate the HTML to Contentful JSON. This doesn’t raise any errors when sending the data to Contentful (we’re using raise_errors: true). In some cases the page renders fine in the Contentful editor, but in other cases I’m getting the following error in the browser instead of the Rich Text editor:

⚠️ Something went wrong. This field editor is broken. Reach out to support.

Digging into the console logs, the only relevant error appears to be:
Error: Cannot get the start point in the node at path [8] because it has no start text node.

Obviously it’s rubbish if content editors can’t see what’s in the data to view it: any suggestions?

Hi @david.mckee, sorry that there was an issue in the Rich Text field on our side a few days ago. The problem has been fixed and you shouldn’t see the error anymore.

Hi Alma and the Contentful Team - we are receiving the same error that David.Mckee has had. This only happens for one of our content producers and not for the rest. We are unable to click into the rich text field and this is blocking us from making any updates. Can someone please provide an update or a fix asap? Thank you