The original is a JPEG and re-saved with a lower compression. Assuming a 59MB images as being a bit too large.
I tried it with images in PNG , JPEG and a pano in DNG (RAW) converted to JPEG.
The result was the same . Just different patterns of red.
I will do more experiment to-night.
Interesting experiment.
I made three pano images.. One in three resolutions using :Ansel 360°, FlowScape panorama, Lightroom panorama from 10 images I took with a point and shoot camera. All were savedd as JPEG images.
The sky using the Ansel and FS panoramas. The same in all three resolutions.
The sky using the Lightroom panorama.
The Lightroom image is 10,00 x 3,600.
Other than the import scale and sky rotation that do not work, I could use my own skies.