I am new here, my name is Aswien from the Netherlands
I bought FCPX Surface Tracker
When I add this to my time line and doing the tracker with the default settings it works.
But when I change the amount for better tracking or smoother, FCP crashed and it is with all the tracking plugins.
Ah, and PixelFilms Studio plugin, who I'm not a fan of, don't like their stuff, not stable, tech support sucks. Did you contact their tech support? That's the first thing to do, they should be able to support their own product better than anyone. I personally am not familiar with this plugin form them, but maybe someone else here is. In the meantime, contact their tech support.
I'm very frustrated with pixelfilm plugins. I can confirm that Propatch 3.0 also crash fcpx and auto tracker doesn't work correctly. I'd recommend you plugins from Coremelt, Factory , Motionvfx , perhaps more expensive but in my case they have shown quality, stability and good support
Best and stay safe