I have been seeing this recently as well. I’ll update my sheet, re-check it in glide, and it looks good. Later, even in the Glide UI (as well as on phones), they’ll revert to a prior version of the sheet. I started adding a version number and date to each sheet update to try and keep an eye on it, and it seems to frequently go back a version or two.
I am using linked sheets to import data, if that seems particularly relevant.