If she hadn't gained any official rank but gone through all the training which the backstory appears to imply, Solia would not hesitate to give her a position with the right to protect her on the spot should it be brought to question. The reasons being the undying loyalty and great dedication she has shown as well as having proven over the years to be more than just highly capable for the position. That and afterwards flashing a happy smile in the direction of Sera.
 
Maybe it never happened because Solia never heard of it (the princess will not be happy with any resentment taking place behind her back...), but that would be her immediate reaction.