From the IO ATC8 spec. "Thermocouple Inputs"
--> Absolute maximum rating ±0.6VDC
It is very easy to get a greater than ±0.6VDC differential between the thermocouple, and the module. All it takes is a poor ground.
Company I work for has > than a hundred of V350-35-TA24 with a similar maximum limit on thermocouple inputs.
As this is on portable equipment, nearly all failures have been due to; too high of a voltage getting to the thermocouple input.
Example Failures...
Powered IR sensor, input shorted to 24 vdc power for sensor.
Ground fault in heat cartridge where the actual ground was not sufficient, and the resistance through the J contact thermocouple was lower than the ground connection..
RF sparks from improperly grounded servo motors. (The problem here is the servo control and "actual" ground may be a long way from the servo motor, which may have a closer low resistance ground through the thermocouple. The spark may initiate a high current flow from another source.)
Regular static electricity sparks.