Tried to find this reported but could not find it. So here it is.
Add some exceptions. Remove one in settings.
Removal of one exception rule
Removal of all exceptions
OnePlus 7 Pro
Tested in a most current dev build. Looks like it works as intended now
Thanks for reporting :)
Hi, reproduced the issue with Firefox Preview Nightly 200323 (Build #20831026) with all testing devices.
Reproduced:

Confirmed that the issue is not reproducible on Firefox Preview Nightly 200325 (Build #20850608) GV: 76.0a1-20200323092419 with:

Samsung Galaxy S9 (Android 8)

Sony Xperia Z5 (Android 7)
