I have the original Mavic Air, and while using the DJI app, will only do active track in Normal Mode. I use my drone for filming waterskiing, which is around 50-55kph.
Air specs are 68.4 kph in Sport, only 28.8 kph in Normal, so obviously not quick enough for active track to keep up...
I have been out fooling around with Mavic on full throttle in Sport mode. This video documents the result and will at the same time show how to enable Sport mode in case you don't know.
How fast have you pushed your Mavic?