[waifu2x.udp.jp] "High" noise reduction can give results between "None" and "Low" on some images

[NintendoManiac64]

On the waifu2x.udp.jp web app, when using the settings of "High" noise reduction + "Artwork" + "2x", some images will have results that are visually in-between "None" and "Low" noise reduction rather than the "High" that it was actually set to.

The two attached images are the only source images (that is, before waifu2x processing) where I've run into this issue occurring (it's more noticeable with the first image however), and for reference using something like Snowshell set to "Waifu2x-converter-cpp" does not result in this bug happening.

And the animated PNG at the bottom is a zoomed-in view of the middle of the first image demonstrating different levels of noise reduction (including the non-bugged "High" setting in Snowshell).