if you had a ride in the area with bad network coverage, your route there will have significat gaps; or if you stopped your car in place A with internet, then moved to place B while being offline and then internet appeared in place B, then Freematics will send just ping events (not location data), and Traccar will show that your are still in place A. I will fix so that it will ping server and also transmit latest location.

dt/<application>/<context>/<thing-name>/<dt-type>

Prefix your MQTT topics to distinguish data topics from command topics