When submitting blurs (mostly removal of false positives), these requests often take a very long time to be processed. Sometimes only some are processed - for example, just now submitted 5 blurs for removal and only two of them actually went through - the other three just kept on spinning.
This is on a decent network connection that averages 2MB/s for Mapillary image uploads.
Might be related to Page not found .
Seems to be the same today.