Cisco 7925 wireless Audio delay issues

[TelecomDudeWA]

We’re having a Cisco Wireless 7925 Audio delay issue. When calls are answered the first 5 to 16 seconds there is not audio available. The issue is sporadic and not easily replicated which makes it very difficult to capture traces. It appears that the wireless is not receiving the ACK in a timely manner once end users accept calls, but cannot absolutely confirm this. Continuous scanning was applied to some of the handsets, but it does not appear to have changed the behavior. We were hoping that more persistent connection would eliminate the delay.

The wireless network is running of 2 Cisco controllers using WPA2-PSK with pre-shared keys. The phones have firmware version CP7925G-1.4.3ES.1 loaded.
Has anyone seen this or have ideas on what can be done?

Thank you

 

[TelecomDudeWA]

We are running UCM Version 8.6.2.21900-5

 

[TelecomDudeWA]

The issue appears in the following situations.
Wireless to wireless
Wireless to Cisco desk phones
Cisco Desk Phones to Wireless
Wireless to external
External to Wireless