MK3S+ bed vibrates violently with PrusaSlicer generated gcode, but fine with Cura generated gcode  

MK3S+ bed vibrates violently with PrusaSlicer generated gcode, but fine with Cura generated gcode

I was printing a few spare parts for my MK3S+ using PrusaSlicer v2.5

Everything seemed working swimmingly until I started to print the parts included Y axis rod holders, I noticed when the nozzle was on these Y axis rod holders, the bed started to vibrate fairly intensely. I stopped the printing as I was worried it would damage the printer.

To isolate the problem I created a new slicer job with just 2 instances of the y-axis rod holders, one rotated 90 degree just in case the orientation was a factor. I started printing and sure enough - when the nozzle was in the open circle area (likely perimeters) which hugs the rod, the speed of x/y axis movement slowed significantly and the vibration started again. I watched it doing this for 2 layers and this happened on both parts with the circle.

I was completely puzzled - shouldn't that circle be a perfect easy thing for the printer steppers? on both X and Y axes you have a perfect smooth sine wave movement - very gentle acceleration/deceleration. Where is the vibration come from???

I then started to monkey around, including moving the parts to different locations on the bed, and try different settings in slicer, like acceleration control, speed, perimeter generation, etc. Same problem.

I then fired up Cura, tweaked settings to match the speed settings in PrusaSlicer and the printer glide through these circles completely silent.

Is this a bug in PrusaSlicer or there I some settings that caused this behavior? 

Thanks in advance!