The default delay between executions is 100ms (RestartSec) which causes the rate limit to be reached very fast.
Just using Restart and RestartSec is not enough: systemd services have start rate limiting enabled by default. If service is started more than StartLimitBurst times in StartLimitInterval/StartLimitIntervalSec seconds is it not permitted to start any more.
Add RestartSec=5 in the service section
Add StartLimitInterval=0 in the unit section
[Unit] Description=Linbpq After=network.target StartLimitInterval=0 [Service] Type=simple Restart=always RestartSec=5 ExecStart=/bin/bash /home/pd9q/linbpq/runbpq WorkingDirectory=/home/pd9q/linbpq [Install] WantedBy=multi-user.target Alias=linbpq.service