Just identified a bug in SPA122. The ATAs both 112 and 122 ( on Firmware SPA1xx_1.1.0_011.bin). ATA reboots when it gets 484 not found. This is causing serious issues in the field as the ATA reboots whenever the customer dials an invalid number by mistake.
Could you please let us know if there is any firmware release that fixed this issue.
Below is link in cisco forum talking about this.
I have also attached the debug taken from the device for your info.