Why is this taking so long to resolve?
It actually was resolved pretty fast. (6 blocks ~ 1h)
There was a second incident on July 5th, with a 3-block orphan branch. There are still v2 miners out there, and the v3 miners are still accepting recent block hashes from them, and mining new blocks on top of them before they have time to validate (or even see) those parent. The fork was blotched.