Openocd no graceful shutdown, blocked ports and conflicts

The openocddriver opens and listens to multiple ports when started (except if last load command is shutdown) by the client.
If the openocdserver/gdbserver is waiting too long for a connection (gdb, telnet, udp) the client throws an error (i assume timeout).
This is not a problem on the client side, but the openocd server does not shut down correctly which leads to blocked ports or libusb access conflicts.
The same problems occur when the client terminates the command that started openocd on the remote machine (via keyboard interrupt).

When openocd is started locally (w/o labgrid), it invokes the "shutdown" command upon receiving SIGTERM, so all ports are closed properly.

Is there any way to implement a graceful shutdown remotely?

This is very annoying because the only way to regain access to the ports and avoid libusb conflicts is restarting the remote machine (or at least the coordinator and exporter).

Start by tracing the openocddriver lifecycle through the openocdserver/gdbserver and the coordinator/exporter, focusing on timeout and keyboard-interrupt paths and how SIGTERM is handled. Done means remote shutdown closes the OpenOCD ports and releases libusb access after failed connections or client termination.