Found an interesting bug.

.. tab:: :math:`O(n)`
    
    hello world

Will render <math>O(n)</math>, while using the directive somewhere in the middle of a tab's title seems to be fine.

Here are screenshots of the problem

Naturally, I'm using Furo.

I've made a branch to show the error. (make livehtml should work for you once you've set up the requirements.)

Later additions:
Also, I've got more interesting variations of this bug.

Play around with the titles, I've tried using :term: with a glossary file, and this just fails at the build stage. Doesn't seem to be a
sphinx bug, but I am not sure.
Log here: sphinx-err-b9355wxr.log

Let me know how I can be of help.