If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content. You can click shield icon for more detail and possibly disable the protection. You can check the Web Console for messages about blocked content.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

I'm confused. I went into Google Docs and saw this problem. Then I loaded a Google help article that mentioned going into Google Drive. I took a look there and ended up going back to Google Docs. But now, the documents that didn't show time stamps in the versions list 5 minutes ago are showing them again. ??

I can't explain it.

Did you change anything in settings? I went into Google Drive as you mentioned, and then back to Docs and they're still not showing. I'm hoping this will just resolve itself in time, but for now I'm still using Chrome for the version history.

I didn't change anything, as far as I know.

If you haven't already, you might clear Firefox's web cache. Sometimes after a site update Firefox will cling to an old version of a script file and that causes malfunctions on a site. Clearing cache will work around that, if it's a factor.

See: How to clear the Firefox cache (only select web cache, not cookies and site data)

If you have a large hard drive, this might take a few minutes.