Hi Red Rebel. It could be you second car is not linked to the colour the app is using in the race set-up. The default cars for a two car race are red and green. You need to match three colours - car & controller on powerbase and car in the app. You can tell the colour in the app by the edge of the driver/car tile in race set-up.
Let us know if that works. If not, give us some more info of what works and what doesn’t - there can be a few other reasons for not counting laps.