ssh connection randomly times out

[James Moe]

opensuse tumbleweed
OpenSSH_10.5p1, OpenSSL 3.5.3 16 Sep 2025
linux 7.2.5-1-default x86_64

I establish a connection to a remote host. After some random length of time
(minutes, hours), the connection becomes unresponsive. After a further period
the connection is terminated:

--[ termination text ]--
Read from remote host sma-station12l: Connection timed out
Connection to sma-station12l closed.
client_loop: send disconnect: Broken pipe
--[ end ]--

This is a recent change. It would seem a timer has gotten involved in some way.
Previously the connection stayed active forever. Obviously something changed.
How do I diagnose the issue?

-- 
James Moe
moe dot james at sohnen-moe dot com
520.743.3936
Think.