Temporal layer shifting on 0.35  

Temporal layer shifting on 0.35

Recently I've found out that my printer (Prusa mk2s) shifts some layers in a strange way. I can see it only with 0.35 layer height, 0.2 or smaller doesn't suffer the problem. The shift starts after a retraction / fast travel / unretraction. The nozzle moves to a slightly shifted position (about 0.3mm off) and prints the next part of the curve shifted. On one of the next fast travels it gets back to the correct position. Slowing down the entirely print on the printer to 50% makes no difference. I also tried to lose one of the belts (the tone was maybe too high) also with no difference. Does anyone knows what the problem is?

Description to the pictures attached bellow:

• First two shots are my 4 testing prints, all off the same model from left to right:
  1. Sliced to 0.2mm - no problem (or not the one I struggle with now)
  2. Sliced with PrusaSlicer 2.1.0, 0.35 mm height, all standard settings
  3. As above but slowed down to 50% (on the printer)
  4. Same model sliced with Slick3 Prusa Edition 1.41.2 (I was trying if it is not a slicer bug)
• Next 4 photos are all made of the second print (but print 3 and 4) looks very similar. Took various angles.
• Last 2 shots are from a print #5 where I sliced the same model with PrusaSlicer 0.35mm but changed the "seam position" to random.

Overall the problem is pretty consistent and deterministic. The print 5 shows clearly that it is caused by the fast travels. I think it doesn't match any case of "layer shifting" or "inconsistent extrusion" problem I could find. Any help much appreciated.

Here are the pictures: