Symptom : On a channel with high utilization and interference numbers, the RRM DCA algorithm might not change the channel when it should. As a result, the channel assignment for a few access points may be suboptimal, which can negatively impact performance.
Condition : If a channel change that is required to avoid the high utilization or interference has an adverse effect on the RF neighborhood, it might prevent the channel change. Release 188.8.131.52.
Workaround : Configure DCA back to aggressive mode.
Let's go to the basics. What is the status between your AP and your LAN link? What model of AP are you using? What model of wireless NIC are you using? What version is your wireless NIC running on? What time was the delay? What is the status of the link between your AP to your WLC to your end device? Do you have TPC/DCA enabled? Do you see any network interference around your wifi?
PS: You do know the Cisco people who's responded to this thread are all from the "Sales" team, right?