ion288 said:
pool #12660. Merged with pool #12638
Since this is pretty much the same issue as what I have asked earlier (ref: forum #187413, forum #187415), I have proceeded to depopulate pool #12660 and delete it.
Edit: For future reference, builders have pool deletion privileges, so I think you can do so for similarly redundant pools if you run into them again. Ones that you think are unambiguously redundant and don't need discussion over.
And, nope, I did not know about it (builders being able to delete pools) either until nonamethanks told me how to delete pools.
Updated