I have found the vertical banding to be an issue as well. Using Sharpen AI 1.4.5, the vertical banding only occurs (for me) when utilizing GPU acceleration and the “Stabilize” mode. It doesn’t seem to matter whether the blur is caused by motion or focus issues. It appears to occur regardless of the photo, but only if GPU acceleration is turned on. Turning off GPU acceleration eliminates the problem. Given that the CPU can get it right on the same photos, I’d have to conclude there is something amiss with the GPU accelerated “Stabilize” mode.
Fortunately I have a relatively fast 8-core Ryzen proc, so using CPU mode is not as much of a slow-down as it might be for others, but it is noticeably slower than GPU mode so it would be nice to see this corrected in future iterations, especially for those with slower processors.
The files below demonstrate the issue. Note that these examples are blown up to roughly 300% to emphasize the problem and make it easier to see, but I am able to begin to see the problem at 100%. It is slight at 100%, but it is there. Not being a guru at programming or compression algorithms, it seems somewhat baffling to me what would cause the GPU to create the banding when the CPU doesn’t seem to do so, given that (I would think) both processors are chewing through the same code.