Why does MultiMedia Console Regenerate EVERTHING after a firmware upgrade

So question for the QNAP staff here..

I just updated the firmware today on my TS-873A. Now Multimedia Console is recreating all the thumbnails, redoing face recognition, etc. This seems to happen after every firmware upgrade - why?

Same thing really goes for QSirch too - it had to reindex everything.

Why does the NAS do this?

@NA9D since Qsirch has the same issue that I am unsure of the root cause.

Could you let me know which firmware upgrade to which firmware and share the debug log of Multimedia Console with us to evaluate what happened?

I had to reboot TVS-h1688x QuTS 5.2.9.3499 for a different problem (ticket) and I noticed that face recognition was regenerating.