[Mac M1] Snapshot To Disk preview is pixelating if using custom proportion

Repro:

1. On a Mac M1
2. Max out graphic settings under preference.
3. Under Snapshot to disk, use a custom size (I used 4096 with constrained propotions as an example). Image attached of the pixelation. (Image 1)
4. Then change from custom size to window size (if you use any of the presets other than window size once the pixelation has occurred, the pixelation will not be removed). Only using Window size resets it (Image 2)
5. Note the same issue occurs if you use one of the drop down example sizes e.g. 1600 x 1200. This is shown in Image 3.

Observed: The snapshot preview is glitchy, has areas duplicated. Note: This only affects the preview window. The actual saved picture is fine.

Expected: No glitches in the preview.

Snapshot to Disk Pixelates on the Custom setting and cannot be reset unless you take back to Window Size.

https://secondlife.canny.io/admin/board/bug-reports/p/snapshot-to-disk-is-pixellating-if-using-custom-proportion

Start by reproducing the Snapshot to Disk preview issue on a Mac M1 using a custom size or a preset such as 1600 x 1200, then switch between preview size options. Trace the Snapshot to Disk preview entry point and compare its behavior with the saved image, which is reported to be unaffected. Done means the preview remains free of duplicated or pixelated areas and resets correctly between sizes.