Knee tracking works beautifully, elbow not so much. My trackers are mounted symmetrically just above the elbow joint. They show in steamvr in the correct position, as does every other tracker and controller, no offset or anything. In calibration, the balls are where they should be, but once i press the triggers, my left elbow is pointed inwards. It still moves independently from the right one, but its just offset inwards.

Swapping the trackers doesn't change behaviour, neither does rotating irl.

(I used the same two trackers in the same playsession on the knees and the elbows.)

In the pictures, im pressing both elbows against my hip, the hip is where it should be.