Hello,
The issue has not been observed previously, at least, I could not find any record of it.
Could you wait until it replicates, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there?
The logs in the file might provide more insight into the issue. Attach this file by editing your question.
Could you provide more details, if you have made any custom device configurations?
Did you perform previous firmware updates with Keep settings option enabled?
Could you try reflashing router's firmware, following procedure detailed here and check, if the issue persists?
Best regards,