2 menubars showing in Writer

I have customized my menubar by adding a menu item. When I do certain tasks a second menu bar appears right below the first menubar. Many of the options are greyed out on the second menubar. This always happens when I “Type some text” then click on View->Print Preview. The second menubar then appears and is persistent as long as I leave Writer open. Closing Writer and restarting removes the second menubar. This also happens when inserting a formula and some other tasks (that I can’t remember - seems random sometimes).

This happens in the Tabbed UI and also when in the Standard Toolbar UI.
I’m using LO on Linux Mint 19.3 Cinnamon

Is this happening because I customized my menu?

Likely. You can try a fresh profile, by starting LO from the terminal with an alternative profile path using the argument -env:UserInstallation=file:///tmp/test.

@jmux I tried it as you suggested and you are correct, it didn’t do it with the test profile. So I assume this is a bug caused by customizing the menubar?