3d camera tracker in after effects

This is essentially not a 3D trackable shot, at least not in the AE realm and not without any static markers. I'm surprised it even solves at all, but that's likely a fluke. It starts over and over again because of course the patterns change all the time, even if just a single leaf is swaying in the wind and that invalidates the existing solve. You could potentially track individual segments and stitch together the resulting cameras, but more or less this is something way beyond AE. I would imagine that you could salvage it with manual tracker placement in SynthEyes or mocha, though, so at least give the latter a try and see if mochaAE is able to generate a stable ground plane for you. Otherwise this is really a case where you may need to plan a reshoot and place soem persistent red crosses on sticks throughout the scene for reference.

Mylenium

Without any specific info about your project, the footage you are using, tracker settings, your computer and so on nobody can tell you much. This is certainly not the intended behavior, but without more details nobody can even guess. From the interanl caches acting up to hardware acceleration problems this really could be anything.

Mylenium