HDRI with VrayBitmap gives different result on opening

[Lindhout]

For a client we render a lot of products with a red coated material. We never had any problems rendering this products. But since we use vray 6 we encounter problems with the interpolation of the hdr.

If we fresh open the file and press the render button the red coated material turns out matte. Then we open the vrayBitmap, switch the filtering to another option and then switch back to the Isotropic. And we the vraybitmap is back to normal again.

This feels like an bug to us. Or do you guys have any suggestions?

In the attachments an example of the wrong render vs the correct render. Also the settings from the vraybitmap and the Vray dome light were the vraybitmap is plugged in.

[hermit.crab]

Could you share the scene so we can take a look?

[Lindhout]

I shared the scene with you.