When using oven customer said cooling fan use to run for awhile after ovn was off now fan shuts off when you shut oven is this normal ?

Most oven’s cooling fans are operated by a reset-able thermostat, once the thermostat reaches a certain temperature it will power the cooling fan and once the oven cools down the fan will shut off. So as long as the oven continues to operate I wouldn’t be to concerned with the fan shutting off.