They've actually been having to dump propellant in order to more accurately test what a Starship in orbit would be like, given they're not flying with a payload that would consume that propellant on ascent, but that they still want to launch with a full tank.
The dumping of this excess propellant actually caused an explosion and loss of vehicle on the second test flight.
That's what they said about the second test flight (and the third), but the webcast recordings looked a lot more like fuel leaks to me, and that is in line with Starship and early Falcon's past issues. I'm going to press X to doubt that the dumping narrative is the truth, since a nice face-saving white lie is in every corporation's handbook.
The dumping of this excess propellant actually caused an explosion and loss of vehicle on the second test flight.