There shouldn't have been any changes to the location bar like you wrote.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Do you mean suggestions in the address bar itself, or in the drop-down below the address bar?

Usually the top line of the drop-down has a light-medium blue background selection bar, and that moves down the drop-down if you use the down arrow key.

I notice you have the Firefox Color add-on. In case this is an issue with your current Firefox Color settings, maybe revisit the site?

https://color.firefox.com/