strange behaviour STL-6303E - dark and stars 'comet-like'

For several days now, I have been having a strange phenomenon with the images from my SBIG STL-6303E. After replacing the dessicant and putting the CCD camera back on my telescope, I have this problem... the stars were suddenly comets with a horizontal tail. I also took new darks and the hot pixels also had a comet tail, nicely in line with the horizontal pixels (see image). I have since replaced the USB cable, also replaced the power supply once. I have also replaced the PC. Removed the CCD camera again and tested it inside the house . But the problem just persists.
Anyone have an idea what this could be? Is this a known problem? How can I possibly fix this ?

thanks in advance !

Erik.

 

There was no adjustment made with the shutter. strange that the problem appears after the dissicant was dried and changed.

 

I also had the same problem last year and then it disappeared on its own, possibly by re-drying and reinserting the dissicant a few times, but am not sure. I have now also re-baked 2x in the oven at 250°C for several hours, but problem still remains. The camera is now defective anyway, I can remove the CCD chamber and see if there is any noticeable 'contamination', although I doubt it. Perhaps the drying pellets inside the dissicant-plug is also no longer optimal, after 10 years of use and having been baked perhaps 40x , or more.
When I look at the hot-pixels we see a kind of capacitor effect here, the charge disappears and decreases, but here in a very short time.

 

I removed the CCD-chip and put them in silicagel for 3 days. After reassembling the camera and did a test, all is working fine again. I think the desiccant is end-of life after 12 years and almost 300 times regenerated. So, problem is solved.