Issue: Existing text detected in 'vB_Editor_001_textarea', overwrite with this backup?

I made a minor edit to the butane wiki, saved it, no problem.
When I went to navigate away from the page I got the pop-up as can be seen in the attached screen shots.
After the pop-up has gone (clicking ok or cancel) the page re-formats itsself so that the content if offset to the right, and consequently half off the screen where I can't interact with it.
Also, the chat box won't refresh, and stays in a 'refreshing' loop (not so refreshing!). This chat box refresh loop is the case for any open df tabs at the time of the
[Textarea Backup] Existing text detected in 'vB_Editor_001_textarea', overwrite with this backup?
pop-up.
Navigating away makes no odds, the only way to return the page to 'normal' is to close the tab.

When I tried to subsequently edit the butane wiki, I get the same.
This doesn't happen if I go to edit any other wiki, but, I haven't actually edited any other wiki, just opened the edit function to see if the bug was present there.

I first got the pop-up when appended my personal notepad/box and went to navigate away, forgetting to have saved it first. I thought, brilliant, a note to stop me losing what I updated the notepad box with where I forgot to save it. But I re-read the pop-up, and it talks about replacing with a back-up. so I clicked cancel.
Then the formatting issue started.

If I click on ok, the formatting issue arises also.

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update:

I think I have temporarily fixed the issue for me. I enabled just the basic text box in my options, disabling the wysiwyg. It seems to work now with out the issues above.