If it is consistently a problem, then lie to the camera about the speed of the film, after you have confirmed the batteries are fresh and their contact surfaces are clean.
Set it to 50 if you are using 100 film. This is not a DX camera; the user provides the input on the base film speed.
Then the old favourite x1.5 lever. So much of the XA got left out when the XA2 came out - at least this thing stayed.