[Firefox] Whitelist mode doesn't work; custom user-agent is still applied on some sites

[raxod502-plaid]

With the extension set to "white-list mode", custom user-agent should only be applied to the sites listed in the white-list. I have that list set to foobar.doesnotexist.com, so the custom user-agent should never be applied. However, when navigating to meet.google.com, the extension icon is orange, indicating that custom user-agent is applied. This doesn't happen when navigating to other sites such as github.com, where the extension icon is orange-blue, indicating that the site is ignored.

Why does this occur, and what makes meet.google.com somehow special in how this extension handles it?

[raxod502-plaid]

Changing to implement the whitelist via "custom mode", where you list each whitelisted website in the JSON object and map it to a user-agent string in the extension settings, rather than setting the custom user-agent through the addon tooltip, does not have the same issue, and custom user-agent is enabled/disabled as expected on all websites.