I looked at you uploaded integrated Flat frame and it looks good with no real issues in the image. However, I note from the FITs header that the exposure was claimed to be 37.58 seconds long and the temperature for the Flat frames was 20.5°C -- at ambient. Those will not cause any major issue but should probably have been taken under temperature conditions more closely matching you Lights and Darks. If the long exposure time is correct and this is a stack of multiple Flat frames, that might be why no banding is seen in the Flat (in addition, of course, to the much greater signal brightness).
I also looked at some the samples you uploaded to your Gallery. They appear to show both horizontal and vertical banding. Have you inspected the Light frames individually to see whether the banding moves around or is it always in the exact same spot frame to frame? That can give a clue to the origin.
Have you considered that this might be a hardware issue? Banding such as seen in the Lights can be caused by noise in your electrical cabling and connections. It could be un-cancelled common-mode noise in the USB transfer or could be conducted noise on the power line to the camera. (Power line noise is more common for such banding. USB noise will usually only be seen on the USB power signal lines.) Both of these sources can be helped with the use of external ferrite cores clamped onto the USB and power cables to the camera. These are available on Amazon and might be available in the Dallas area at electronics retailers. They are easy to attach as an experiment and will generally have no side effects on your equipment. Just clamp one each onto the USB and power feeds near the camera.
Whether or not this is electrical in nature, can you tell us more bout your setup? What power source do you use? How is the camera attached via USB? Does it go through a USB Hub? How long are the cables? Do either the power or USB cables pass near a source of EM radiation like a WiFi antenna?