all dvrs rewinding

This afternoon and tonight I have tried to watch 7 DVRs.  Every one has rewound at the 45 minute point.  One 2 hour DVR has rewound every time I have tried to watch it.  I found another showing of it and DVR'd it.  It also is rewinding.  This happens several times per week.  Accessibility keeps telling me it is the box.  Two weeks ago they installed the 4th box.  It made no difference.