Since the update, bugs have been more prevalent. Engine noise getting stuck is a big one, but no servers today have had any AI traffic. This is most notable because the weekly challenge is impossible to complete in freeroam without cars, and I haven’t seen anything online about the issue. Surely being in dozens of servers with 40+ ppl, someone else must have noticed this? I’m confused.
I just noticed the same thing. I’m trying to complete the 4th chapter of the Summer “Kettle of Fish” weekly challenge right now.
I just drove from The Gables player house in the southwest part of the map all the way to downtown Edinburgh in the Northeast corner and then drove up and down the main drag in Edinburgh and I haven’t seen a single AI car anywhere. The trams are still running like normal on the main strip, but no cars at all, every road I try is completely devoid of traffic.
As Roscoe said, it’s going to be just about impossible to complete this challenge without any traffic to dodge 
I just went for Horizon solo to do that Kettle of Fish challenge, there’s is plenty of AI cars on that mode.