So, there was...is an issue with Squish in Kyber. I think because K1 doesn't get promoted, they get neg squish instead of positive squish like all the other leagues where players finish the season in Div 1.
There was an attempt to modify the squish formula to fix the fact that K1 had shrunk in size dramatically. At that point, these weird and certainly unsuitable accounts starting appearing in K1.
I don't think any explanation has been given as to why. It appears it could be something to do with the 'legacy' score. Or it could be something to do with original GP placements.
It certainly needs fixing.