Cannot find source of overallocation

[nesskramer]

My manager recently asked for my assistance with resource leveling of the schedule for our project. Per his request, I am using the Resource Usage sheet, filtered by Overallocated Resources, to view the team members who need leveling. I was going by resource, looking for the days with overallocation, and decreasing how many hours were being spent on each task assigned to them so that they hit the 8-hour-or-below mark.

I currently have an associate who has tasks assigned over a 12-year period, and though I have gone over and over each day of that period, I cannot find a single instance in which she is scheduled for greater than 8 hours in tasks. My manager has reviewed her tasks multiple times as well. Nothing we can find appears to be a trigger.

Any advice? We're at a loss.