bitcoind starting and then quickly shutting down automatically

[Bitcoin]

bitcoind starting and then quickly shutting down automatically

Lenovo E460, 8GB RAM,
Fedora 26,
bitcoin core command line version 0.16.0,
All blocks completely downloaded on a flash drive with 256GB capacity.

I rebooted my machine today without stopping the bitcoind before and since then the following happens:
1) starting "bitcoind -daemon -datadir=/path/to/flash/drive"
2) I see with "top" the process 'bitcoind'  running  for about 30-45 seconds
3) Suddenly under same process id the process names changes to "bitcoin-shutdown" and disappears a second after.
4) Stop or new start of bitcoind is not possible, message is "Error: Cannot obtain a lock on data directory /path/to/flash/drive. Bitcoin Core is probably already running."
5) Only way to start bitcoind again is to reboot the linux. Then loop 1)-5) starts again.

Any help appreciated!
Thanks!

Source: bitcoind starting and then quickly shutting down automatically