We’ve had the same experience on a new SQ7. We had it running out of the box for four weeks on firmware v1.2.2 with no issues. We then had our first lock up after upgrading to firmware v1.3 last week, and it did the same at rehearsal today. (I didn’t think to try unplugging the network cable to the router, but restarted the SQ7 instead.) Both times it happened when a song had finished at the vocalist went to adjust their SQ4you settings. I’d be interested in the outcome of the OP. Now that the SQ4you app has been upgraded to 1.3, I take it we can’t roll back to the SQ7 firmware v1.2.2 as the 1.2 app is not available. Fortunately it hasn’t happened during a service. I’ll look into our DHCP settings.
Beyond that, I will add that we’re loving the added sound warmth the system is giving and it’s a pleasure to work on. We’ve come from a LS9.