*Update - I'm moving the controller command up to the top of my post to avoid sending you down wrong path (my issue is more "inaccuarte high physical errors in Airwave) where as yours could be an RF 2.4GHz problem*
Our TAC case is ongoing and they checked with controller team - controller team informed me to use the following command to check for current physical errors on the AP - however, pointed that this is not "historical" but a snapshot:
show ap arm rf-summary ap-name <ap-name>
I currently have a ticket open with TAC concerning a similar issue that started with 8.2.5.1 (AP-225s, AP-205s, AP-205Hs) - the key symptom in mine is essentailly - you can't have a "great physical error per second than total packets".
Back when we were on 8.2.5.0 - noticed that statistics/graphs for the 802.11bgn (2.4GHz Radios) were missing/blank with maybe one single record every other day - the 802.11ac (5GHz radio statistics) were fine.
You can view these statistics by navigating to the "AP Monitoring" page and clicking each of the individual radios - then choosing "Radio Errors" from the drop down-menu.
Worked with TAC and they upgraded Airwave to 8.2.5.1 which resulted in the graphs down below. The graphs were now being populated, but the statistics weren't matching up. "Physical Errors" was greater than "Total Packets" on the 2.4GHz radio. *Note we lost Channel Utilization, Goodput, and another graph with this upgrade" -> 8.2.6 has resolved what we lost in upgrading to 8.2.5.1- but we're still running into the "Physical Error" graph issue on 2.4GHz.