Thank you for the link to the document you sent. I will dive in and read it. I am the network engineer, and we have a voice engineer, so we're both tackling the issue. We are only allowing the phones to operate on 5GHz. There was a recent change after we rolled our firmware back, since we have large site (98 APs, mix of MR32 and MR42s), to where we expanded the channel width from 40 MHz to 20 MHz. Regarding the channels the phones are operating on, I will need to take a look. The issue happens in certain parts of the building, which leads me to believe it's more of a noise/interference issue (hence the recent site survey, and modifications to the channel widths). Knowing that 802.11r is not recommended to be enabled unless you're operating on the 11.0(4) firmware is good to know as well. Thank you for your help thus far.