Tor Browser 14.5 100% CPU IndexedDB IO Thread

My up to date Tor Browser 14.5 (based on Mozilla Firefox 128.9.0esr) shows 100% CPU. Results into very unresponsive experience.

I was looking for reason and found IndexedDB IO Thread from page about:processes

I changed config to find it:

toolkit.aboutProcesses.showAllSubframes true toolkit.aboutProcesses.showThreads true

This reproducible, so I could debug further if told how to find cause of this? I can supply more information.