I have not noticed any banding with my QHY268M, which I have had since Spring 2021.
My challenge with the 268, which I love (and bought the 268C as well, but have not yet used), is moving dust spots between flat and light acquisition. This is generally only a single spot, out of many, on the sensor cover glass. I speculate that 16-bit sensors have many more problems with dust spots shifting on the sensor compared to 12-bit sensors when nothing is changed due to the noise floor being 16x lower making them visible. Since day one, I have noticed many more spots on the 268 that would be near the sensor that those in 2 year use of my 183; again I suspect much lower noise floor being the cause, e.g. similar spots are their in the 183, but buried by the noise floor.
Small changes on the 268 are noticeable than would be buried in the noise floor with my 12-bit ASI183mm-Pro (used for 2yr prior to the 268, with few flat issues). I have made after the fact flat spot repairs (or changes to a residual spot on master light) using PixelMath that are sensitive to ~0.000010 differences, which is close a 16-bit step of 0.000015 (1/ 2^16), supportive of my quantization noise floor cause. By comparison 12-bit step is a much larger 0.000244, of which a 0.000010 difference would not show up.
Edited by SilverLitz, 22 June 2022 - 12:23 PM.