Coap Server releases port with a delay after termination
This behaviour is not noticeable during normal use. However, during the integration tests, the CoAP servers are started and stopped quickly one after the other. Often the CI jobs fail because of this (example: https://git.informatik.uni-hamburg.de/sane-public/wot-servient/-/jobs/113447)
The problem is either in the coap library californium or in Java's DatagramSocket implementation.
The current Workaround seems to help only partially.