If you feel like it is not acting right, please open a TAC case, so that they can take a closer look. It is entirely possible that your A band has not changed channel or power, depending on your spectrum. If it has changed channel or power, that is incorrect and it needs to be looked into.
Type show log wireless all | include <name of ap> and see if there were any channel or power changes.
You can also type "show ap debug driver-log ap-name <name of ap>" and see if it references any channel or power changes.