Fantom tracking data

It has been happening ever since I started using Mocha (Since Mocha 4 I think).
When I track perspective - it goes wrong, the track deforms a little, the footage is not perfect for tracking, so I go a level lower, tracking pos, scale, rot - still not good, go once more down, tracking only position.
The track still deforms - even with just position tracking - it’s as if a new track doesn’t overwrite the original perspective track.
I swear to God I’ve had instances when even deleting all the keyframes from the layer, and retracking just the position - still the original perspective track was showing through - mind you, after deleting the keys, the layer was not moving so it seemed all tracking data was gone.
In these stubborn cases the only way is to just create a completely new layer and track that one - and it tracks perfectly. I’ve found no way of getting the stubborn layer to behave correctly.
Now this happens very rarely and is almost impossible to recreate so I never reported it.
But still, has anyone had similar situations.

If possible - please provide a screen recording to show this the next time it happens.
I’ve been using Mocha since v1 and don’t recall this specific behavior happening.

Are you keyframing the spline and then going back and retracing?

Curious if anyone else has seen this. Will need reproducible steps if possible.
Thanks for sharing.
Ross