This is a particularly annoying issue that I discovered this morning. Last night, I scheduled a post to be "published" later today (actually, about 30 minutes ago). When I saw my blog, however, the post hadn't been published even though the time passed and the post itself was in Published status.
The clocks changed last night here, and my server time is accurate, but according to my blog, the timestamps were off by an hour.
In the WP options, the "Times in the weblog should differ by" was correct, somewhat. I am in -5 GMT (EDT zone), but WordPress does not seem to be aware of this new timezone shift. Basically, when I went to "write" a new post, I saw that WordPress was off by an hour -- an hour earlier. (I had to change it to -4 in order for WordPress to see the right time. It saw 10:30 instead of 11:30.)
I suppose this is a bug, and I'd love to know if anyone else is encountering this as well.