I updated to the most recent nightly on windows and all my active tabs are not loading. Just giving favicon spinners. The only exception was a tab that was a single image and one that was reader mode. Presumably this came from cache?

A Mac user in #nightly:mozilla.org indicated the same behavior. They said that things worked in private windows and safe mode, but I did not try testing these. I've updated to a day old build in order to keep running with this profile.

Based on reports in Matrix I've frozen updates on the nightly channel to Firefox-mozilla-central-nightly-20200519094847.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Duping forward to bug 1639429 as higher level of detail and ni set over there.