I have hardly used my copy of FF6 until I read about this wavelet filter. I downloaded it, and it installed OK and opens up in my FF plugin to Affinity Photo.
I was trying it on an image of a prickly shrub, which I had cropped to square. I ran the filter and the preview produced what I guess is a standard output with eight images compressed into the original sized square: the six wavelet images, the residual and the original. The limited documentation says that I should now stack the wavelet images and the residual. However, I see no way of saving these seven images separately, although I could save the composite, squashed version.
Having saved this composite, I was not able to close the plugin and return to Affinity. The Windows Task Manager said that Affinity was using 5 GB of memory. (It typically uses c400Mb.)
I also tried it using the standalone version of FF6, with the same result, but no memory leakage.
John Rostron