odd config behaviour

[M Rubon]

I have a customized sshd_config file which I had previously just
copied into /etc/ssh on an Ubuntu server.  On a new machine I thought
I might try being better behaved and instead copied my config in
sshd_config.d/sshd_config.conf

So it kind of works.  The non-conditional config is correctly used
when I restart sshd.  But config within a "Match User" seems be parsed
and then silently ignored

Match User foouser
   Banner /tmp/specialtestbanner     # this banner file is weirdly NOT output
   # When uncommented this garbage line generates an error, so is being parsed

Everything works perfectly if I copy my sshd_config.d/sshd_config.conf
over top of /etc/ssh/sshd_config (so no include is being done).

Testing done on OpenSSH_8.2p1.  I don't see any man page caveats about
nesting Match within Include.  I can try reproducing on a modern
openSsh next week if that is useful to anyone.

Mike