Excel iOS app not autosaving and freezing.

Same problem with Excel on on both my ipad and Iphone for more than a week.   When I try to close the file on ipad/iphone - More times than not, Excel screen goes grey (forever) when I should get the saving/closing spinning wheel.  I never get a time out or connectivity error but I suspect I should.  Have to force close and reopen excel before the GUI is usable again.  This occurs on ipad OS and iphone OS 26.7.  Issue occurred with last minor version of Excel mobile as well as latest version.  Same file from OneDrive using desktop version of Excel opens, saves, closes with no problems every time.  Sometimes updates made with desktop version will show up on ipad, others times not.  Issue is almost certainly a comms issue between mobile excel and the backend OneDrive (SharePoint Online) infrastructure.  Have signed out/in to mobile excel, reset app, reinstalled app, restarted phone and ipad, etc... Nothing seems to help.  This is a ~500kb spreadsheet I update 3 - 6 times per month for 4+ years mostly via ipad... never had this problem prior to the last ~1-2 weeks or so.    I've left in app support request days ago and nothing but crickets.  WTF MS Support?