Same issue here on PC.
Steam
1.06
My Team
50% race
No Error Code
AI ~75
Went from 1st to 20th, while setting fastest lap on the final lap
I had lapped Latifi about 3 laps early, up several seconds on Leclerc (in second)
Had used a few flashbacks
Only incident was a love tap on Kvyat into turn one when I came out of the pits
I restarted the session, but have not tried it again.
I lucked into a one-stop strategy by getting out of Q2 on Mediums while the rest of the top 10 were on softs, forcing them onto two stops
Screencaps from the results screen:
Edit: Ran race again, came in first again but the issue did not manifest this time, only real difference was that I did not lap any backmarkers due to being caught in traffic (overly aggressive teammate) coming out of the pits