These are Unix Datagram sockets. They work like UDP (connection-less protocol), but on unix sockets (like /dev/log). They are mostly used for logging, or maybe process/thread messaging/synchronization.
zmconfigd has a bug what causes it to allocate new unix dgram sockets in an infinite loop.
The probable cause is this:
It was written in python, compiled ...
I found a solution - but my understanding of it is limited.
Running sudo conntrack -D -p udp in the host apparently resets something and allows for the real origin IP addresses to be reported.
Apparently this needs to be done after any restart of the container.