Forum Discussion
Modified Date and file changes
Currently and so far I know, OneDrive does not have a feature that allows manual control over whether the "Modified Date" is updated. The behavior is fairly standard across all versions, whether you are using OneDrive Personal or OneDrive for Business.
Some programs, particularly Office apps like Excel, Word, or PowerPoint, can cache changes locally. If those changes aren't synced yet or auto-saved and aren't uploaded right away, the modified date may not reflect the change right away.
Server-side changes only:
If a file is edited server-side only (e.g. via OneDrive's web app) and isn't saved, the "modified date" may occasionally not update until the change is committed or synced across all connected devices.
I've never tried all of this, but maybe it'll help you a little.
My answers are voluntary and without guarantee!
Hope this will help you.