Question about (my) Chosera 5k

Hey there,
I own a Chosera 5.000, and have owned a Super 5.000, a shapton pro 5.000
and still have a cerax 6.000.

I am quite fond of the choseras but I am experiencing a problem with the 5k right now.
My 5k (even after lapping with shapton lapping powder and a reference plate,
and extensive cleaning) leaves nothing near a mirror polish.

I am used to some degree of scratching from a 5k stone. All the others did that.
The Chosera leaves a very uniform scratch pattern
But it leaves scratches, that my Naniwa Super 8.000 won´t get rid of.
How´s that?!

Does anybody else own a chosera 5k and can comment on this problem?
Do you guys get scratches from the 5k,
that an 8k stone can´t completely earase?

I narrowed the problem completely down to the chosera 5k.
If I leave the stone out, I get most perfect results.
Btw. the edge it produces is still great...

People here use chosera a lot, I am sure you will get answers there.
As far as I know Chodera does not leave finish as bright as superstone, but I can't comment on the inability if your 8k to erase the scratches from your 5k stone.