PDF file with missing text that comes and goes

New Here ,

I'm viewing a PDF and text is missing from it - eg 't' from products Other people view it on other devices and it is complete. When I close and re-open some text reappears. I've uninstalled Adobe reader and reinstalled but problem persists. Other PDFs are missing graphics too. This is crazy as I use PDFs to proofread creative work and this makes it impossible! Is this a bug?