Layer shift print problem

I got this problem which I couldn't define the root cause. Layers shift randomly it happens even at lower heights. It seems to be a mechanical problem probably y axis. What's your opinions

Is your extruder calibrated? It's hard to tell from this photo. Do you get a build up of plastic on each layer on which the print head catches? If it is catching, you will hear and see this happening during a print.

Have you check the obvious like belt tension and that the head moves freely in the x and y direction.

Less obvious is the setting of the current adjustment on the stepper drivers.

Is your chape meant to be a test cube? If so, you can improve your print by having a little gently cooling.

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Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9

Acceleration, if you're experiencing what I did, layers shifting plane without any explicit cause. Just moving a long and then it decides to move to the right 3mm. Yeah, dial your acceleration down to 500 and work up from there.

Yep, I agree with hibijibi, it probably acceleration in your firmware.
Mine was at 3000 and layers would step over at speeds above 30mm/s, I lowered it to 1000 and works fine.