glitchy banding when using gaussian blur

[qendl 6]

First image shows a single pixel layer on gray rectangle background with no blur. Second picture shows exact same project with Gaussian blur added via fx on the pixel layer. As you can see, glitchy vertical banding appears.

[Sean P 1,370]

Hi qendl,

Would you be able to attach the document you're applying this to please, along with some information about what Mac you're using, what macOS you're on etc?

Thanks