After a lens was dropped, I performed the unthinkable. I disassembled the lens (NOT in a clean room) and was able to reseat the third element, fixing the problem completely! In order to pull the element, a custom “tool” was needed to uncrossthread the retaining ring. A little CAD was used to get the angle and placement correct for the screws to align with the retaining ring’s notches. Even though the process wasn’t pretty, the result is a perfectly working lens, saving someone over $7000. https://youtu.be/D4dHr8evt6k