Problem with alignment

[[Al...]]

Hello again, i'm here becouse i can't go out with an alignment problem. I'measuring the final part of an exhaust system which is basically a pipe. The first part i have measure without porblem with a simple rps alignment. But now i have to measure a new piece (same part n°) with the same program. I start manually, the machine does the first loop without problems and after it goes out of range in z axis and finish with the error. The alignement is done with the cylinder-plane intescection of the two ends and a point in to block the Z.After the first loop i can see the position of the current points which are totaly out and i can't uderstend why this happens and why the first time the program works correctly and now not. I share an example.
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[[Al...]]

Edit: Problem solved, the cause was the piece positoned too high 🫣
But i still don't understand why the first loop worked correctly.