A Microsoft file hosting and synchronization service.
Have you checked if you have a problem with the upload center? review the following information:
https://support.microsoft.com/en-us/office/dele...
Also, if possible, try to remove the outdated documents from that folder (Possibly the documents in the cloud) and save the most up-to-date documents in another location.
Check if the local documents were deleted if so, copy the documents that you saved in another location in the folder