Did you enter the dive manually, or was it recorded by the device? Manually enetered activities do not apply for badges. If it was recorded by the device, could you post the temperature graph of that dive?
My device won't go scuba diving. So I have to enter them manually. Temp was 3c as it was in iceland. Why don't manually added activities count? That's not fair when one dives but doesn't have a garmin dive computer.