The wash cycle starts with a 5 second delivery of water then stop

The machine is a Bosch Classixx 1400 Express. The cycle starts then there is no activity whilst the time remaining clock counts down.The soap tablets remain dry so I took the drawer out to observe what happens at the cycle start and there is a 5 second delivery of water to the r/hand pre-wash part of the drawer. Once the cycle gets to the rinse part the rinse indicator light flashes on and off and the time remaining info goes out.