For some time now, probably close to the last three years I have noticed the date and time received by caller ID information fluctuate radically, from one hour +/- to several hours.
In the past it seemed to be a problem during the change on/off of DST here in California, namely Los Angeles County.
It seemed that when I changed from POTS service for home internet to ATT U-Verse is when it started happening. Currently the home phone and internet are through Sonic.net which on the hardware side is still provided by ATT.
The business line is still on a POTS connected to a 5ESS, which blows my theory out of the water that U-Verse was the problem. Caller ID from the 5ESS also fluctuates.....unless of course only data received on CO1 adjusts the TA-824s date and time, and CO2 beyond is ignored?
To the point, I have spoke with support from both ATT and Sonic.net. I was told that Panasonic equipment was the "worst" for interpreting Caller ID data accurately.
I've had a KX-TA824 installed here which is now 10+ years old. The KXT-VA50 is now 9 years old.
For approximately the first 7 years Caller ID Date and Time never faltered.
I don't think it's the fault of Panasonic's equipment. I think ATT is merely trying to lay blame elsewhere?

Your feedback is appreciated.
Don Resor