A patch has been applied to bring significant improvements around the services that start races. This should ensure races start on time during normal service.
In the last couple of weeks under the huge demand we're experiencing, many races had been starting a few minutes late due to the amount of strain the demand was placing on the servers. They were basically struggling to cope with the demand, but the issue should be resolved now.
Please let me know in a reply if you see an improvement or not.