XB7 8.5p16s2 — 2.4-GHz IoT devices dropping and rejecting correct Wi-Fi password

XB7 8.5p16s2 — 2.4-GHz IoT devices dropping and then rejecting correct Wi-Fi password

Has anyone else seen problems with 2.4-GHz IoT devices after their XB7 updated to:

CGM4331COM_8.5p16s2_PROD_sey

I’m in Colorado and have an XB7 / CGM4331COM Revision 2.0.

We have 10 Amazon Smart Thermostats that all previously worked reliably on the same Wi-Fi network. Seven still work, but three progressively became unresponsive, with Xfinity showing their last connections as Oct. 4, Oct. 11, and Oct. 14.

I factory-reset one of the failed thermostats. It now refuses to reconnect and reports an incorrect Wi-Fi password, even though the password is definitely correct and seven identical thermostats are still connected using it.

The XB7 has been rebooted since the first failure, but additional thermostats subsequently went offline. Other network devices generally continue to work normally.

I’m particularly interested in hearing from anyone who:

• is running 8.5p16s2 on an XB7/CGM4331COM;

• has had established 2.4-GHz IoT devices suddenly drop offline;

• has seen devices reject a known-correct WPA2 password; or

• found a fix other than factory-resetting or replacing the IoT devices.

If Xfinity Support sees this, I’d also appreciate help determining when my gateway received 8.5p16s2 and whether there are any known 2.4-GHz compatibility issues with this release.

I’m avoiding another gateway reboot/reprovision for now because I plan to retrieve the local logs first.