I fixed this by setting my EV4 to static addressing.
I don’t see anything about the DHCP server, but when a DHCP request comes in, the connection to the internet-based server is dropped. It seems to recover eventually, but Home Assistant can’t control the state of the alarm panel (DSC).
It’s possible that the internet service doesn’t expect a “few second max” delay in establishing the new connection. In fact, in an existing TCP session, there should be a number of retransmissions, with binary-backoff, before giving up on the flow.
Anyway, it’s nice to see my alarm and set and reset it as needed!
Thanks,
Ambi