I just heard from a QNAP support agent July 20:Sneeze1066 wrote: ↑Tue Jun 23, 2020 11:02 am I've had a response to my support ticket advising that the issue has been identified and a new release of HBS3 will be available shortly to fix it.
"According to our HQ, there was a bug on HBS3 that causing the issue. It's a known issue that has been fixed on Hybrid Backup Sync V3.0.200619, Please help update your HBS3 to latest version"
Unfortunately I don't see this update available yet. I asked the agent when it will be released and was told there is no ETA.