Just went back to do some old quests that i skipped and i checked the guild roster to see who was online. My status said i was offline and hadn't been on for 41 minutes.
The only reason i could think of that caused this error was when i mapped to beacons perch.
I tried talking to my guildmates but nobody responded.
Relogging fixed the situation but if i truly was offline in the eyes of my guildmates, i can see this could need attention.
Anyone had this problem before?
Guild roster saying i'm offline
Tactical-Dillusions
GraceAlone
I've forgotten to put myself back online in the chat preferences. In your friends list is an option to show your status...don't know if that was the case though 
Madjik
I have once or twice, usually when I switch between characters.
wallin
Happened to me once. I started talking to some guildmates, much to their surprise since it showed me as offline. (I hadn't changed the chat preferences or anything).
Algren Cole
my guess is that the checksum for "online" wasn't set when you logged in...or it was triggered by an action. It's a common problem with any online application/database. there really isn't a fix for it unless it happens often. It would be nearly impossible for ArenaNet to replicate the situations by which it happened to you.
Asplode
currently, it says I've been offline for 4 hours even though I'm online