Hi,
So, this is going to be a bit of a guess i'm afraid.
I'm pretty sure that Brightmail 6.0.1 was released before the US changed their DST dates. So maybe in a couple of weeks, when it passes the old DST timeframe, it'll show correctly.
I'd recommend getting on to version 6.1 for many reasons but you might also find this issue fixed there too.
//ian