As mentioned elsewhere it's not actually upside down but seems to be tipped over about 90 degrees.
The author is being coy.
Because it could be a error in the instrumentation.
The photo clearly shows it's upside-down.
They need more data to verify that the camera isn't also upside down.
But then how will we prove the planet isn't upside down?
Just ask the Australians.
Imagine the vehicle upside down and the camera twisted upside down so the photo is right side up but conflicts with the other sensors. In that situation I would take the rest of the day off.