The problem with the bevel shaft affecting the planet theory is that it would probably affect first stage. Not to say it didn't end up that way, we don't know. First stage sun was worn uneven. About the only thing that one could logically speculate to be related.
Could also be a general local starvation of oil in the epicyclic module. Clogged passage could do that.
To me, looks like gears ran very hot and discolored.
Chip detector won't work without oil return flow.