Sibilance from Van den Hul Colibri

I have the light weight gold coil acrylic body XGP LW Colibri on a Well Tempered Reference Arm and Table. Though it is a dream with about half my collection, on the other half it has excessive sibilance, sometime with a searing high end that ruins the playback
I have about 200 hours on the cartridge, and have done some limited adjustment w VTA and loading to no avail.
Any vdH Colibri owners with experience who notice this ?
Has anyone come up with a solution ?

vdH Colibri, Well Tempered Ref w Arm, Spectral DMC 20 ( no SUT), moded Luxman 3045MB tube monoblocks (Russian EL 509II output tubes) 800 ohm loading, von Schweikert VR 4 jr w "EuroMod". Cables are MIT/Spectral
If you sure you set it up correctly, I would complain to VDH....I've seen them come from the factory defective
I've never owned a Colibri but have heard it in many high end systems. It is EXTREMELY finicky with respect to set-up. When not properly tuned, the sound will tend to be as you describe and there is a very fine line between heaven and strident.
Dear Shussbliss : As Jazdoc said it " there is a very fine line " down there that will be tammed after the VdH cartridge fine tunning that VdH makes for your cartridge by free after your sample achieve 300 hours of playback.

So, IMHO you don't have to worry yet. You have to wait for that VDH cartridge fine tunning before any " serious " in deep cartridge evaluation.

The Colibri is a top contender. I own the 0.22mv cooper coils model that IMHO performs better than the silver and gold ones that I heard it, I don't heard it yet the platinum one.

Btw, I don't load the Colibri as high as VDH recomend or as you do but as low as 100-150 ohms. You can try and see what happen.

Regards and enjoy the music,