I have noticed some issues over the last 4 weeks with online refresh for Excel that appears to be corrupting the version I open in Excel Desktop app. I can also replicate it.
I have been using a spreadsheet, with only powerpivot and a data model (no power query), for over 12 months with my team, its accessible on sharepoint.
Recently, I have noticed that after on ok online refresh online, when i then open the file in the excel desktop, followed by another refresh , I get a crash to desktop. I have tried to fix, but the file is basically ruined. Everything i try results in crash to desktop inlcuding inspecting document and running in safe mode makes no difference. It seems as though the data model in the excel app is broken but it still works in online