Colombo spindle ATC 5HP HSK 50

Need Help! I have a CNC machine, this time I would want to upgrade it to Colombo spindle ATC 5HP.
I bought this used PDS G.Colombo RA 110.22 spindle ATC 5HP 18000 RPM HSK 50F water cooled, and tried to upgraded my CNC machine,
and now I have a big problem ( I THINK ).

It looks like everything works OK except on the collet chuck ( Tool Holder )
and spindle inside leaves strange marks ( Please see the pictures ) It does not look like scratches but looks more like marks.
We tried installing brand new Techniks HSK 50 collet chuck ( Tool Holder ) and it begin making new marks.
Please let me know what is this mark and how to fix it in the cheapest way (this is a hobby machine ).
And make sure the spindle doesn't make new marks.

Another question if you know or if you can check on your spindle, please let me know how its supposed to be.
We made that if sencor S3 is on ( tool enable ) after that the tool clamped and waited till sencor S4 is on, after that it continues to work, and it still gives air pressure 7bar to the tool clamped cylinder.

Please let me know if this is wrong or maybe I need to turn off the air pressure to the tool clamped cylinder after sencor S4 is on.
Please let me know if you know any infomation.

Thanks for any of your help.