This happens to me from time to time... I just ignore it! It seems to happen when I am unplugging and plugging it back in a lot but that might just be me.
I think you only need to act when it says the boards need updating.
This also happens to me from time to time. This is a feature of the Arduino IDE that is intended to help people who just plugged in a new board, but don't have the board's support package installed yet. It should never appear when the package has already been installed, as is the case for you, so this is a bug in the Arduino IDE.
As @matt_lee_smith said, you can safely ignore it, but it is kind of annoying. You are welcome to submit a bug report to notify Arduino's developers about the bug:
Ideally, you would be able to provide a detailed set of instructions in the issue report that can be used to reliably reproduce the bug, but I don't know if that's possible with this particular bug.