I didn't see a response from my first questions, but I believe I know what the issue is and how to deal with it.
I believe what you have encountered is the "time adjustment" feature of most modern phone systems, where the time is adjusted for each new call (or voice mail notification) that comes in on your phone line.
This also means that your service provider has NOT updated your service to reflect the correct time, now that Standard Time has kicked in. Once your provider updates their system, your time should read correctly again.
BUT, if you want it to be correct NOW, you can turn OFF the "time adjustment" feature and then set the correct time again, and it should remain correct so that it does NOT updated based on the time information that is coming from your service provider.
To change the time adjustment feature to be OFF (or manual), please do the following on ANY HANDSET in most Panasonic systems.
1) Pick up a handset while NOT on a call.
2) Press MENU, then # ***** 2 6 (this takes you directly to the Time Adjustment section).
3) Use the UP or DOWN arrows on the handset to point to "Manual".
4) Press SAVE (to save your selection) and then press the OFF button (to exit programming).
Now go back and set the correct time, and save that information. VERIFY the time is correct (what you just set it to) on other handsets in the system, and if correct, you should be all set.
Please let me know if that works for you, or if you have any other questions.
Thanks, ***** *****