Tour of London stage 1

Hi, quite new to Zwift so not really clued up on how it all really works.
I have been doing an FTP builder now for 4 weeks currently on day two of week 4. I also signed up to doing tour of London which little did I realise it clashed with my ftp ride.
I finished the ftp that I was doing and saved it as normal and then started the tour ride although 15mins later than the stated start time.
Once started and after about 4 minutes I got you’ve now completed stage 1 an£ the ride finished? However the ride only shows 1.3miles done.
Is this because I had also done the ftp on the London course/route?
Thanks