Limits don't appear in equations after saving

I’m entering an equation in the form

lim from x toward 2 {{ lline x - 2 rline } over {x - 2} } = “?”

Then I save as a power point, then retrieve it later, and it comes out as something like:

size 12{ { { lline x - 2 rline } over {x - 2} } } {}

The limit is missing.

Not an issue saving as .ppt and .ppts with LibreOffice 7.0.6.2.

I see that it is a very old question.

But is is always a valid tip:

Always use the native, international standard ODF file formats.