Occasional blue light on satellite

The blue light will reportedly come on when the satellite switches between 2.4 and 5 GHz backhaul.

I suspect your 5 GHz wireless backhaul connection is marginal, and is switching bands occassionally. Wireless signals will very substantially over time, so the GUI report of a good connection is just a snapshot in time. You would need a substantial signal margin to completely avoid temporary issues, and the Orbi has no quantitative report of the backhaul strength.

The backhaul uses the same frequencies and channels as any other WiFi device, so if you have the satellite in a location in your house that's problematic for WiFI, the backahul will experience the same issues.

If everything works, you could ignore it. If the light bothers you, or you encounter perfromance issues, you might want to move the satellite to a better location, that's closer or has fewer walls between.  Sometimes a few feet is all it takes.