I tried to use JumpHost via my server running AlpineLinux -- these guys set "AllowTcpForwarding no" and i only append all changes in order to make merging after updates (much) easier. After hours of failed attempts and google-sponsored searches on the boys toilet walls i finally realized that it was the "AllowTcpForwarding yes" that i appended, it will will be recognized only when placed in a "Match User " block, but not at the toplevel. Looking at servconf.c it seems as if that happens because at parse_mulistate: *intptr is only overridden if it is (still) set to -1, could that be (i have not verified this claim). If so, then i would hope for either that this restriction is removed (i do not understand it, i think use cases are thinkable), or that at least with -vvvvvvv there would be a warning on "rejecting overwrite of configuration value XY".
I'm not sure what you're requesting. It might be more clear if you gave an example of your working vs failing configurations. The configuration is first-match-wins and this isn't limited to parse_multistate. Changing that would literally break the world's working configurations.
I have not read the third sentence of the manual page in many years. Sorry for the noise. And rereading the report as such.. You have found out what i was talking about, congratulations. But as a small feature request, just a little -vv or so verbose message that an attempt was made to overwrite a yet existing (explicit) setting would be wonderful. Also, neither sshd(8) -t nor -T warn about this. In fact -T warns 'Match User' in configuration but 'user' not in connection test specification. when i force the problem, but this message as such i really do not understand. "steffen" and "web" or both local users. Hmm. I think this is unrelated, however. Thanks!