Not sure what triggered it. might have been pet death.

Should be Razesinge left of my player plate. seems to have reverted to the pet owner in this case?

This happens when you take control of a vehicle you can attack from, such as the warframe on argus, as while you are in the vehicle your character is classified as a "Pet" and switched to the pet frame.

When you leave the vehicle and the unit frame changes back to your player, the pet frame is not changed leaving it as your information instead of your pet information. Both player and pet unit frame needs to be updated in this situation.