I tried active track yesterday once.  It seemed to be OK.  Today I again got a notification to update my software.  After updating I took th P4 P to check out the active track again (absolutely wind free - perfect conditions).  I activated active track, identified myself in the green box and clicked OK.  From the start the P4 P became aggresively unstable...  It was like it got full power fwd and immediately thereafter full power in reverse.  I hit pause, stopped the process and landed.  I rebooted the P4 P and the controller and tried again.  Same outcome.  Any one else picked this up?

Yup.  Same thing happened to me.  But, admittedly, I don't know how to use active track or any of the other intelligent modes very well -- this is my first drone.  But the footage I got when trying to use active track was nauseating.  It was rapidly moving forward and reverse.

I tried Active track for the first time yesterday - very unimpressed. I didn't see what you described but the opposite. It was a bushy area with a trail through it. I selected my brother on his mountain bike, and he rode off slowly. The P4P followed him, but veeeeery slowly - to the extent that even at a slow pace he lost it before the trail took him around a tree. The P4 reached the tree and started to jerk severely around, putting it precariously close to some branches of another tree. I took control at that point, and tried to angle the P4P around the tree, but it often just refused to move. I gave up at this point.

I have to assume that the P4P is just too temperamental in bushy environments - it's sensors must see too much and it's logic gets confused. Anyway, a fail from my mountain-biking brother...