Edge 830 has stopped rotating through data and map screens while cycling

I have 4 screens set up for road cycling on my Edge 830 (Speed, elevation stats; gear and battery info; upcoming climbs etc; map).  Usually it rotates through the screens as I ride but has now stopped doing so and simply sits in the 1st screen.  It does respond and change to maps when a turn comes up but the other screens no longer appear at all.  Any ideas on cause and remedy?