That’s very odd, because you should definitely be seeing _log.qo events w/ gpsmax like this appearing whenever your Notecard updates its location and performs a sync:
Are you seeing any _log.qo events for the problematic device?
For reference, my config looks something like this:
{"req":"hub.set","product":"x","mode":"minimum"}
{"req":"card.location.mode","mode":"periodic","seconds":3600}
{"req":"card.location.track","sync":true,"heartbeat":true,"hours":-5,"start":true}