Services stop responding after disconnecting from wifi overnight

I'm going to have to wait for it to do this again to get more details, but it happens probably once per week.

Each night at 8pm, my Mac Mini runs a cron CLI script to turn off the wifi. Each morning at 6:15am, it runs a cron CLI script to turn it back on. I also tried using Automator applications, and the same problem occurs. Scripts follow.

In the morning, when I sit down at my computer, sometimes things are very broken in strange ways. It almost seems like a system service has quietly failed or something. I cannot restart - the Apple menu works, but choosing Restart or Shut Down does nothing. Most applications will not launch, or will launch and immediately fail for an unknown reason. Finder often won't open. Most of the time the wifi will be on and my firewall will be detecting minor traffic.

I often leave my work applications (Sublime, Adium, Skype, Chrome) open overnight - I work from home - but this strange crash only occurs when the internet connection is disconnected overnight. No error messages.

Crons:

0 20 * * * /usr/sbin/networksetup -setairportpower en1 off

15 6 * * * /usr/sbin/networksetup -setairportpower en1 on

I think the alternative is to just shut down each night, instead of being a lazy bum.

Any ideas?