Hi,
I made a software update over DI Software Update and then flashed the firmware version 1.4.4 to my BrickPi3.
After the updates the set_motor_position method results in a permanent oscillating of the motor around the target position.
I’am using some EV3 medium and large motors and default settings for the PD (kp=25; kd=70)
I had accidentally failed to adjust a copy-paste remnant that caused the default value of set_motor_position_kp to be 70 rather than 25. It was fixed here. Running an update will pull in the fix. Note that the bug was only in the Python drivers, so you won’t need to update your FW to fix it.
If it’s actually set to 25 (default when the BrickPi3 gets powered on) and it’s still oscillating, you could try adjusting it to 20 or 15. Take a look at the comments here for more information on the effects of adjusting the constants.