Well as said above:
and there isn’t even a guideline for such cases.
But yeah, I wouldn’t have changed the sort name to “BDP, Harrison” there.
Here this guideline 1.a. could take effect: “Middle names and nicknames should be treated as a part of the given name.” So if the artist name only consists of parts of the given name they shouldn’t be sorted.
PS: Here the artist was added with the name already added - more than 2 years before the legal name was added - and then simply never changed.