I call that "Character" and would leave it. You probably wouldn't get those spots to take dye anyway. They didn't the first time.
The reason why the blank was stabilized with a colour was to enhance the burl eyes within the burl sapwood, that otherwise would have a very boring colour.
Those burl eyes together with the heartwood are very oily and that is the reason why the dye did not penetrate however and as I said, that was the intended result so, even if you would try to dye those areas where the dye didn't come through, it wouldn't accept it, unless you would use something that would me more like a paint than a dye and then coat it, the problem would be, it wouldn't allow fine sanding before the CA/finish application, any small attempt would rub the stain off those uncoloured areas, again.
There is nothing to worry about with that blank, sand it fine and CA it well, the colours will become very vivid, almost like, they want to jump out of the wood...!
Good luck,:wink::biggrin:
PS: One can only be surprised on what one can receive in a order as a "gift" mostly in the "short" department, some really gems go as a thank you, sometimes...!
Cheers
George