CM1150V modem for Xfinity - daylight saving time being sent to phones

We have a comtemparary Panasonic cordless phone system. Our system is modem-ed by a Netgear CM1150V on Xfinity. Since installing the new modem in July, incoming calls are passing a time value to the phones that is adding an hour to the current time (not every call - just once). The time is set on the phone by setting time on one handset and they all update. It then gets the call time from the Caller ID. Our previous modem, and Arris, did not change the time on the phone. We are in Arizona which does not go on DST. It seems like DST is being applied to the time and tosses in the extra hour. I worked with Xfinity support up to tier 3 escalation and they cannot find the problem. Tier 3 contacted their engineer team and got back to me telling me that since I own the modem, even though Comcast/Xfinity "supports" it, I should reach out to Netgear myself rather than them exploring their Xfinity-to-Netgear contacts. I cannot find a setting on the modem to manage a Daylight Saving Time setting. Again - when we had an Arris modem, the time did not get changed on the phone system.