Alternator assembly question

I'm replacing a noisy front bearing, and am confused about a thin washer that was between the bearing and the front housing (fan side). The bearings are already sealed, and the ID of the washer is the OD of the shaft. When I'm assembling everything, this washer gets sandwiched between the bearing inner race and the fan spacer, causing the washer to rotate within the cavity when thing would be tightened down. This doesn't make sense to me. What am I misunderstanding or mis-assembling?

Thanks!

The larger od spacer goes against the bearing and the fan. It has a large od. but should not touch the alt housing or the bearing seal when spinning. On the front side of the fan there should be a thicker, but smaller od spacer, and then the pulley.
There are also 2 different thickness spacers on each side of the rotor, inside the case, with the thickest being toward the front.
That's a 10si alternator.

I appreciate it!