Hello everyone,
I am facing the same issue, running from command line works , even my data is replicated across the nodes and everything is synced and running.
However, starting it as service and with (TimeoutStartSec=400 in mongod.service) leaves it working for those 400secs (the files are also fully replicated and properly inserted inside those 400 seconds). I also see no issue in log files, so if anyone can contribute to this issue it would be helpful !