RFP issues with performance metrics such as .measure and .mark, were resolved in FF111
- 1811567 - Remove RFP Restrictions on the Performance APIs Remove RFP Restrictions on the Performance APIs
- 1810741 - RFP breaks Sync login RFP breaks Sync login
I do not recommend you ever toggle RFP or start in normal mode. Just wait for Tor Browser 13 and try again