Unplugging the smartthings hub is more complicated because there might be a cloud to cloud component, to be honest I don’t know how the Hue integration works anymore.
If it happens when the hue bridge is disconnected, then, yes, it isn’t any of your automations on any platform because they all go through the hue bridge not directly to the bulbs.
Check the IDE and see what zigbee channel your hub is operating on, and check the Hue app and see what zigbee channel your Bridge is operating on.