Got the lens back from the service. Took almost a month. First it went to Sweden and they sent it to Germany. Service report reads that they did focus point adjusment and optical check. Now those soft edges are much better. Still it feels like that my copy is not quite 100% what it should be because top edges have more sharpness than bottom edges. I tested it with F2.8 for infinity focus sharpness. Not really using that much those wide apertures for infinity focus though and closer focus distances do not produce that obvious differences what I have seen. Center area is really sharp and there it seems to perform 100% and top middle edge is quite close. That is probably the intended quality for all edges.
A bit shame that premium lenses can have sloppy quality control. What I learnt from this that I do not trust anything what manufacturers say about premium quality control. Finnish shops have 14 day return policy for web purchases, so I will do these tests first no matter what brand or price it is.
Here is some comparison shots. Right top image is the worst edge before service which is left bottom edge. Left image is the same after service. Left bottom image is the best edge which is top middle edge. Right bottom image is right top edge which shows how much better that corner performs compared to worst corner. These are 100% crops.