Well, the good news is Matt who also responded to your post has seen this scale issue before & feels it will clear up with the next shed.. So, please let us know if the next shed clears this up.. And, hopefully i am wrong!
Also, now it's on more than one of your animals, so i am even more interested in finding out what it is?
Maybe try changing that walnut bedding to newspaper.. I don't know if this issue was caused by the walnut bedding but, I have only heard bad things about it.. In my opinion any bedding that lends itself to spot cleaning is a poor choice for reptiles. i might get slammed for saying that but it's my opinion!
Keep us posted
~ Mike Russo