The update improved the handling of cars and AI driving but pitstops are still an issue.

The AI doesn't stop unnecessarily during the first few rounds anymore. However, the fix seems to be a bit to simple. Now they just stop when fuel is about to run out (unless heavily damage), which means they enter the pitlane at the same time meaning some of them might not be able to refuel. And they even do that if it's the last lap. And in longer pitlanes they still do the double stop with the first and last crew.

Basically there are two separate issues:
Double pitstops and unintelligent fuel dependence.

The first one should be easy to fix. They just need the same checks (fuel and damage) that are performed while following the race path in the pitlane.

The second is probably harder to fix but there might be a workaround: Mandatory pitstops. The easiest way would be to require every car to stop once after 50% of the laps are finished and then assign them a random number of 0 to 3 (or less If less laps remain). This way they would not stop to early (as it was the case before the Patch) and not all in the same lap as they do now. The check for a completed pitstop would have to be whether the car is completely full, has fresh tires and undamaged after the stop.

Obviously intelligent pitstop planning by the AI would be the best. This would require the AI to calculate the amount of fuel needed based on the first lap and then check which lap is the earliest and latest to stop. Then a random or damage dependent choice can be made. In addition to that the later stopping cars should just refuel as much as they need to comfortably finish the race.

I hope we'll see some of these improvements in the near future.