That's because Zulu is Zulu (GMT) regardless of local corrections for Daylight Savings Time. And the forum has a user-selectable option to automatically update for DST... although I wonder if it actually has all the worldwide DST settings in the software, or if it's only for the USA.

I had to logout to see it - but forum default is GMT-8 (Pacific Standard Time). Right now you and I are on Eastern Daylight Time, GMT-4.