I was exploring Firefly "text to image", trying to refine the images that it generated.
As I fed Firefly back the previously generated image (for either structure or style), it produced false-positive errors, that the reference image "Violates Firefly guidelines".
This is the image it had problems with. (And a few similar renderings of the same design).

It was challenging to work around this issue — as it would remove both the "Structure" and the "Style" uploaded images. I would then need to reupload both and reset the corresponding variables.
A semi-related issue I encountered... was regarding so-called "copyright" issues. Some of the generated images Firefly produced caused the "violation/validation" dialogue modal to pop up, suspecting it was a "Copyrighted Image" from a some other source. So it didn't recognize its own renderings.
One would think a “30-year Adobe Veteran User” should be a badge of Distinction or a discount for glasses.