Here is a link to a YouTube video that Ralph Davis did on the "Over Night" change https://www.youtube.com/watch?v=m0BON9anGVE
Some thoughts about your post (I am not trying to argue, just discuss and point out the observations that I have made, I only have 3 seasons of breeding, so there is still a lot that I have to learn):
First - if it were bacterial, wouldn't it be more likely to spread? Especially to snakes in tubs near by?
Second - I have had this happen now twice in 2 years
Third - it has happened to animals sired by the same male
Fourth - it occurred to animals with the Orangebelly gene, not any of his normal offspring
Fifth - I have never observed an unusual deification from either of the 2 animals that this happened to
Sixth - neither animal exhibited a thicker than normal shed, all of their sheds have seemed very normal
Seventh - the change has been very gradual. You wouldn't really notice it unless you had other examples of the morph to compare to until they are almost Axanthic like
Based on these observations, I do not think what is happening to my animals is the same as what Ralph Davis has documented in his video. I also would think that there might be a genetic component because it has happened to 2 animals 2 years in a row, both from the same male, both with the Orangebelly gene. That is a lot of coincidence. Just some thoughts and observations.