Was playing in a regular track worldwide on CTGP, look up from my phone after track selection and a custom track has loaded. Takes ages to start, half the room (presumably vanilla players) disconnect (whilst waiting I took the website screenshot), the remaining few including myself then start the race. All other players are clearly on the same track as myself as they are on the same lines etc. Next race after is only me and one other player on DK Summit. Not sure who picked the track.