It looks like a simple feature request. Or it could be a bug.
You posted this in Feature Request. I also don’t know if it would be better as a bug report. I did move it over to Bug reports.
I can reproduce this. It happens in the help vault, with no custom CSS.
I’m just not sure if it makes sense to expect anything different. This is how the CSS renders the math font. Does it make sense to actually include math in a title? Do you have an actual example of using this? (Legitimate questions. I’m not sure!)
I agree. This is a bug (?) that does not need to be fixed immediately. This is just a simple report.