I was a person who mentioned this issue with my STT8300. Just to clarify, for me it is with bias frames and flat frames, not darks. It seems very much related to exposure length. A two-second delay improves things, but doesn't absolutely eradicate the problem. I have the same problem on two different laptops.
I haven't had a chance to update SBIG driver and firmware yet, to see if it makes a difference. There was a mention of something about USB communications in one of the SBIG descriptions, not sure if it applies to STT8300. Fingers crossed.
Best regards,
Craig