Anth ASI6200MC, impossible to display in preview.
My guess is that ZWO could have changed how the image is downloaded.
In the past, I have seen terrible Moiré patterns when an image (from a Bayer color camera) in the Preview screen is pinched at certain magnifications (i.e., you see cross-hatched patterns on the screen that comes and goes depending on the magnification). [Check Google for "Moiré" if you are not familiar with the term, or how it is caused.]
That was an indication that the image was scaled to too small a size at the Raspberry Pi before it was sent to the tablet. The under sampling thus causes Moiré.
It is possible that ZWO has corrected that bug, and is now sending a larger image from the Raspberry Pi , so that when it is rescaled to fit the Preview screen, Moiré does not occur. ZWO never document changes, so we will never know.
If that is what they did, then the problem could be insufficient RAM on the tablet to hold the larger image before it is scaled down to the Preview window.
I don't have any tablets with small memory (I always max out on RAM when I buy my tablets), so I cannot test it out.
You can try to set the Preview screen to use Bin 2 to see if it helps.
Be sure to set the Binning to 1 in the AutoRun setup to make sure it does not default to the Bin 2 from the Preview window.