DISREGARD POST. USER RESET FIXED THE ISSUE
My 520 is setup as follows...
Heart Rate Maximum: 160
Resting: 60
Based On: % Max
... but each zone is showing 100% - 100%.
I never had to adjust these manually before. The funny thing is that each zone does seem to report properly when I look at my stats in Garmin Connect. I thought the Zones on my 520 were supposed to reflect the percentage and what the BPM for that zone was?