Delayed pump action on Symbol

I wouldn't worry about it.

The cold water is limited to the volume in the pipes and therefore when the tap is switched off the pressure builds quickly and the pressure sensitive switch in the pump switches the pump off.

The hot water tank has a much larger volume of water in it so it takes the pump a few seconds to build up enough pressure to switch off. The pressure is then such that the hot tap when opened can flow a few seconds before the pump starts.

If you have the original Shurflo pump fitted then the pressure switch can be adjusted. There is a screw in the centre of the end of the pump (the black plastic end). To decrease the pressure at which it shuts off, turn the screw anticlockwise. Only a quarter of a turn at a time and then check the delay before the pump switches off. Open and close the tap a few times after each adjustment to allow pressures to settle before evaluating the time. You should eventually arrive at a position where both the hot and cold taps allow the pump to operate a similar cycle.

However as I said at the start, I would leave well alone.

Peter