Math formula is modified after file is closed and opened again


I’m facing a weird trouble using LibreOffice Writer with embedded math formulas (inserted in text with Insert → Object → Formula…). The problem is: the original formula data look like n=0, but when the text file is closed and opened again, the formula data is appeared being modified and looks like size 12{ ital "n="0} {}, which is weird and embarrassing.

So, my question is - is it possible to protect formula object from any modification and/or styles applying on LibreOffice Writer application close?

Thanks, any help would be appreciated.

P.S. I’m using LibreOffice on 64-bit Fedora Linux.

I’ve found a workaround.
The original text file, containing formulas, was in .doc document format. Exporting the file to .odt format has not fixed old formulas, but all the newly-created formulas look clear after closing/opening.
The source of the problem probably lays somewhere in exporting from .doc to .odt routine