OK, I think this thread has split a little. Encryption/obfuscation is tripping the "ransom-ware" disdetection, but I don't think this is related to the "RPS" issue, which I'm not seeing at all.
It's possible this might be a Microsoft Graph API issue; I see a similar question (unrelated to rclone) at com.microsoft.graph.http.GraphServiceException: Error code: InvalidAuthenticationToken Error message: Unable to initialize RPS - Microsoft Q&A which was asked yesterday and reports issues going back a week.
It may be a volumetric thing based on number of requests; my uploads are typically a few hundred 5Gb files, rather than thousands of small files.