This is because the viewer doesn't receive a timezone from the server but bases its displays on Pacific Standard Time.
However, it still expects to receive notification from the server as to whether or not Daylight Savings Time for PST is in operation.
This commit introduces a new DSTZone setting in the [LoginService] config setting that accepts a list of timezone names valid across different platforms to calculate Pacific DST.
If you need the old behaviour of calculating DST based on the local timezone of the server running the login service, then please override DSTZone with "local".
A mailing list announcement will be made later.
Thanks to Olivier Van Helden and Gudule Lapointe for determining this behaviour and providing this patch.
From http://opensimulator.org/mantis/view.php?id=5972
cccef2e56d