SAMG55 freezes at negative temperature

We are faced with the problem of using SAMG55 microcontroller. After several months of continuous operation as part of G3-PLC communication module, we met firmware hanging and negative temperature.
Time before failure: 3-4 months and freeze at -40 ℃). Over time, the “freeze” temperature rises, after another 3-4 months freezing temperature -20-30 ℃).
Several thousand devices has this problem.
Same problem at different systems, firmwares, and KIT SAMG55-Explained.

Hello Aha,

For assistance regarding this issue we can conduct a failure analysis. Contact our Customer Service at customer.service@digikey.com with pertinent details along with your Customer Number and any Sales Order number so that we may begin this process.

Thank you,
-Troy