It looks like the cause of this could be the mix up of gateways and devices as per my previous comment. From the logs it looks like you have changed the types of the device IDs between gateway and device, and in some cases a device with id b827eb0a0ee8 has connected as a gateway (shown as just a device in your screen shot) and subsequently been disconnected because it attempts something unauthorised (probably attempting to connect an unregistered device; ie the client ID mix up issue).
Auto registration of devices is temporarily disabled and so if a device does not exist (because the client ID is wrong) then the gateway device will be disconnected.
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solved Device connected, but ‘IBMIoT: Error: Connection refused: Not authorized’ message keeps popping up