Hey Pekka!
One thing I noticed was your PT settings, note the first setting (samples per pixel per iteration) doesn’t actually increase your quality, it is what we use to spread load across multiple GPU’s.
For your motion, you should be increasing your motionblur frames to something around 30 or 32 for this type of camera motion, and then slowing increasing your path traced samples per pixel. How this works is each iteration of motionblur is effectively one sample and you multiply that by your path traced samples per pixel.
I use this for instance for a heavy fog scene:
This is effectively 5 x 32 = 160 samples.
I’ll have some take a look at the jumping shadows, looks like occlusion artifacts?