Sometimes, we're going to accidentally revert RecommendedVersions
This morning, somehow we accidentally pushed a version of the website from yesterday, which didn't recommend Tor Browser 4.0, so all the 4.0's out there decided they need an update, and started flashing the exclamation point to their users. Even after we pushed the correct version of the RecommendedVersions list, those browsers never checked again to notice that actually their version is now fine. They blink the exclamation point forever.
Mike checked, and simply restarting your Tor Browser is enough for it to pull a new version of the RecommendedVersions file. So it's not so bad.
But maybe it would be wise to continue the automated periodic checks, so running browsers will recover from this situation?
Since we moved the RecommendedVersions file to the website, which has many people modifying it for many different reasons, it's likely that this mistake will occur again someday.