i don't know where you already have looked, so i have to guess:
kernel.log
system.log
selfmon.log
fallback.log
I'm curious: why do you think the ASG has restarted itself? Are there any traces in the kernel log? And why do you think it's proxy-related? have you found any evidence in the logs?
one reason for unexpected restarts may be that the Kernel crashed - in the default setup, the ASG reboots in this case. For debugging, i could just disable that reboot, so that we can make sure if this is caused by the kernel, or something different.