Perhaps it shows that the ancestors of the Picts actually migrated from the region around Poland but a few stayed behind.
That is an interesting possible concept too. I was thinking more along the lines of Picts hitching a ride with Vikings to the area. As we know from the Mediterranean seafarers, they would shanghai sailors from all regions and cultures when they were needed. They were not purists when it came to labor. I don’t think the Vikings were either. Could have even been Pict royalty on the run buying passage to safety. Wonder how the timelines match up with the Roman Conquest of Britannia? Lot of Picts on the run at that time and they were already connected to the Vikings...