Hiding an SSID would require a reboot, so the AP could stop broadcasting that SSID and remove any users who would have previously seen it. Adding an assignment rule to a user profile could potentially change how all connected users are classified, so that is again something I would expect to take a complete configuration to update. Editing an assignment description doesn't sound like it should require a reboot, but I'd need to see specifically what you're updating to be sure.
The main causes of delta updates failing are either that the configuration change requires a reboot, or that the firewall port is not open correctly.
Hi Keith, it depends on what changes you're trying to push out. If a change is too big for a delta update, the delta update will fail and you'd need to push a complete configuration. If you're making minor changes that won't affect how the wireless traffic is processed, I'd recommend checking port TCP 22. We use different ports for the delta and complete configuration upgrades, so if one is failing it's a good idea to check the port. Hope that helps!