Even before the leap to Quantum by Firefox, I was already having issues with the LastPass Add-On. It did not retain the preferences I set and it was acting "clunky" unlike before when it was doing just great. After Quantum, I sent a support ticket and I got a reply on 12/29/17. I guess I did not read the reply carefully. I just downloaded the latest LastPass Firefox Install which did not solve the issues. Well, today I read the support ticket again which specifically said to download the Universal LastPass Installer, uninstall my current version, reboot and install the Universal version. I did that then did another reboot/restart of my PC and after a few tries (3 or 4) on Firefox (logging in and out of the Add-on and/or restarting Firefox), I got it to work. My preferences are retained, my vault is displayed correctly, the remember my PC/device feature works, etc.

I just rated it 4 stars because there's always room for improvement. And I'd say that the engineers should be on top of this as this app is vital to users' security. You need to be a step ahead.