So what happened in Mar 2018?
Just to be sure: you looked at the gateway’s Traffic tab in TTN Console? (That’s different from the application/device’s Data tab.)
You’ll want two browser windows open, for both the application/device’s Data tab (which if TTN accepted the DevEUI, AppEUI and AppKey should show the Join Request, plus the assigned DevAddr, with an orange icon), and the gateway’s Traffic tab (which should show the Join Accept along with a green icon). If you see any output, clicking an item will show more details.
The gateway’s serial port output should also show things like:
LORA: Accepted packet
MQTT: Sending UPLINK OK
…and for the OTAA Join Accept, in the gateway that has been selected to transmit it:
MQTT: Received DOWNLINK
Or failures like:
LORA: Packet dropped! Bad CRC
(Which might certainly happen for radio packets from some other device.)