Hi! If you switch on safety systems (AWS and similar) you get emergency brake warning on departure, though you have green light.It takes about 15 - 30 secs to release it. Then everythings allright. Could be like a similar problem att Ebbsfleet - Tricky Tunnels, which was fixed by the latest update patch. I didn't see any train on the map either. You can avoid this happen if you wait and switch on the safety systems after passing the departure signal.
I had a similar issue with another service, I re-ran the service but when departing the station where I had the issue I pressed the Q button and all was good.