Yes, screenshots are needed.
Banding is caused by insufficient bit depth. Assuming you really are seeing exactly the same thing as the OP, the usual explanation is that you are working in 8 bit color depth. Then there are only 256 discrete steps from black to white, and those individual steps are clearly distinguishable.
But even if the image data are 16 bit, your display is still 8 bit! So if you see banding with 16 bit files, it's in your display path, somewhere from the video card to the panel itself, including calibration tables. It could also be a bad monitor profile.
The thing about banding is that it's cumulative. Repeated brush strokes will exaggerate it. Subsequent components in your display path can add their own banding, and these will go on top of each other, all contributing to final on screen banding.
... View more