@MartyZ 

I do not know of any setting that will trigger a reboot on error. Most routers have the reboot schedule you can use most likely in advance/system settings. That may help.

Best if you disconnect all of those added units an put them back a few at a time to determine if one is causing the issue. 
 

Also if using QoS, try turning it off. 
 

let us know what you find.