Actually, the auto-assault stops when it switches from player owned to neutral. However if you click it again, it will continue to auto assault.
Also, you had to have been clicking it over and over, because there are gaps of a few seconds between each attack in the game log.
12:39:59 AM rdsrds2120: sorry, I had a lot of lasagna tonight
12:40:06 AM rdsrds2120: I'm pretty out of it. CRAAZZYYY NIGHT
12:31:04 * Metsfanmax quit (kicked from Social by Metsfanmax - reason: haha gotcha now)
12:59:32 * #1_stunna gropes blakebowling