I've got a 580 EX and it just got weird... There is about a 60-90 second delay between the time the off switch is flipped and the unit shuts down. Also, when trying to power it up, nothing happens until I press the pilot button, then the unit comes to life... any thoughts? Have a wedding tomorrow (of course) and this is a big problem 😞
From what you describe this does sound like a strange issue. You may try to use a different set of batteries. If you are using a battery pack, please disconnect this and use AA batteries instead. If you are using the flash off camera I would recommend using it attached to your camera instead.