Possibly you just need to force it to reverify again. If this is still the state of things try setting `app.update.lastUpdateTime.xpi-signature-verification` to 0 in about:config, and then restarting your browser.

But no guarantees. Do you have reason to believe the addons are still installed?

That worked, thank you!

As a side note, the value for that setting got reset after I restarted firefox.

Also, I uninstalled the fix by simply removing the extension in about:addons. Is this the correct way to do it?

Yep, you're all good. I'm surprised it let you remove the fix from about:addons but I wouldn't worry about it.

That value resetting is expected, it's the time when Firefox thinks it last checked signatures, it resetting just means this convinced it to recheck as intended.