User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0

Steps to reproduce:

Since the 19th May update to Firefox Nightly (not the stable Firefox, 78.0a1 64-bit), my webpages load indefinitely and I tried refreshing the Firefox Nightly. It was working until I enabled all my old add-ons again. Hunting down the add-ons gives me:

1Password Extension for 1Password Password Manager affects all my pages.
Ad-Blocker for Youtube affects specifically YouTube.

Disabling these two cause the issues to disappear.

Actual results:

Since the 19th May update to Firefox Nightly (not the stable Firefox, 78.0a1 64-bit), my webpages load indefinitely and I tried refreshing the Firefox Nightly. It was working until I enabled all my old add-ons again. Hunting down the add-ons gives me:

1Password Extension for 1Password Password Manager affects all my pages.
Ad-Blocker for Youtube affects specifically YouTube.

Disabling these two cause the issues to disappear.

Expected results:

Webpages should work with all the add-ons just like before the Nightly update.

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