3d text & motion tracking & mysterious twist

what am i missing ? my text twists as movie plays.

I have a simple movie with a little panning.

Created NullObject, did MotionTracking with 2 points, applied.

In photoshop i made a TEXT and applied Repousse.
Imported into AE, copied Controller & PSD into main comp.
Parented controller to NullObject

All Good. My 3d text sticks to the point i want. cool.

But on my second clip i've turned the TEXT to stick it to a wall in the clip. And as the clip plays the text appears to turn a bit more one way and then another...

Sorry if its not clear, i dont have anything to post to illustrate at the mo...
And what's really annoying is i did all this last year and got it working perfectly. the text stuck to the wall (of the alley scene) as the cameraman panned and walked.

Please any suggestions.

scale and position.

For the 4 seconds or so of clip i want the text to appear in, the cameraman does not move his feet. Just a little panning.
But thanks for the idea...

I've just redone my tracking with all 3: scale, position, & rotation. Now the text also jerks away from the camera after 2 seconds. (it moves further into the shot).
And it still twists about.