Text Block Duplicates "UL" Tag Every Time Page is Saved

I thought maybe this was what was fixed in 3.3:

– folder config-templatebuilder: fixed an issue with the visual editor adding unnecessary html characters and tags

… But maybe not. I’m running 3.3 and every time I save a page with this in it …

<ul><li>asdf</li><li>asdf2</li></ul>

… I get this:

<ul><ul><ul><ul><ul><li>asdf</li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>asdf2</li></ul></ul></ul></ul></ul>

What causes/solves this? It’s driving my Web Producer nuts.