We have many ISR4451 routers. We've been using DNAC to upgrade code and so far it's been fine. These routers and stand-alone (no SD-WAN) and have the boot var set to the .bin file. Recently, after DNA-C does an upgrade, the router fails to come back up after reboot. It looks as if it is in controller mode and we have to manually issue a 'controller-mode disable' command to recover. We've had three of these recently. I'm not sure what has changed. Any ideas?
