Here is a piece of zshall(1) manual page:

.so man1/zshmisc.1
.so man1/zshexpn.1
.so man1/zshparam.1
.so man1/zshoptions.1
.so man1/zshbuiltins.1
.so man1/zshzle.1
.so man1/zshcompwid.1
.so man1/zshcompsys.1
.so man1/zshcompctl.1
.so man1/zshmodules.1
.so man1/zshtcpsys.1
.so man1/zshzftpsys.1
.so man1/zshcontrib.1

There appears to be three problems with displaying this page:

1) no default path (/usr/{share,local}/man) search happens;
2) no $NAME.*z* search suffix implied (the page hasn't got any prior knowledge
about its compound parts, but we do know that all the pages are compressed in our
distro; so the search with the implied suffix should also happen);
3) when the absolute path with the actual suffix is given, groff cannot
understand compressed files; so there's a nice portion of shit on the screen. 
And this is the best you can get.

So here's a bunch of problems.  Since I can fix the manual page to source the
real files, the most obvious problem is #3.