An oil supply leak would not cause chipped vanes; ingesting something solid would. Since you did not do the install, the question would be if the used turbo was in this condition prior?
Poor lubrication of the turbo sleeve bearing can wear them and lower the rotational speed. That may have caused the higher EGT temps, or the turbo does not match the original vane design. There were a few changes to the turbos over the years.
I'd be looking closer at the vane at 11 o'clock. Chipped vane turbos have run for some time without issue, but it's not something I would care to do. You never know the fatigue, and there would have a minor balance issue.
Poor lubrication of the turbo sleeve bearing can wear them and lower the rotational speed. That may have caused the higher EGT temps, or the turbo does not match the original vane design. There were a few changes to the turbos over the years.
I'd be looking closer at the vane at 11 o'clock. Chipped vane turbos have run for some time without issue, but it's not something I would care to do. You never know the fatigue, and there would have a minor balance issue.