A Microsoft file hosting and synchronization service.
Hi,
I understand why this bothers you. It looks like OneDrive sees folders as fresh stuff when it re-uploads or re-indexes things. So, the Modified Date on your folders changes to when it synced, which stinks. The great part is your files inside should still have their old dates, so your document history is probably alright. double-check by opening a few files to confirm their timestamps.
If those folder dates really matter to your work, you could try pausing OneDrive, restoring from a backup (if you got one), or using File History to get those folder dates back.
Are the dates on your actual files also changed, or is it just the folders? Also, are you syncing to OneDrive for the first time, or did this start after a recent update?