ABB TZIDC Digital positioner no reach the auto adjust

Hi,
We installed a new ABB TZIDC positioner on a linear regulating valve equipped with boosters with a supply pressure of 06 barg, the positioner was well positioned mechanically in the linearity range between the two angles of rotation -28° and +28° for a linear actuator

according to the documentation provided with, after the launch of the auto calibration procedure, it quickly goes from step 10 to 40 then it takes a little time between 40 to 49 where it gets stuck at step 49 and sometimes it returns from 49 to 40, so the auto adjust can’t reached (See attached document page 16), in this case, what is the problem and How long it will take for a complete auto adjust?

The Zero and stroke adjustment has been selected, the positioner has successfully adjusted this two parameters, during the test of the valve operation with the injection of the setpoints (4-20 mA) it was found that it is unstable with remarkable oscillations( overshooting).
Sincerely,
 

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