I think I know why this is. Back in the days I used skins, I would never be able to join any eGO server after it crashed, but I think I had figured it out.
eGO has measures in place in order to remove the default CS:S server restrictions that exist on Weapons Skins. However, these do not apply on the first map when the server is started. They only apply once the level is changed (on subsequent maps changes after the first map, which is always the default map).
The reason why your skin never worked on canyon was because the measures in order to allow gun skins was not in place, as the server had just crashed and it started up again on canyon (the default map). The level needed to be changed from something other than the default map in order to have the skins allowed on the server.
This happened to me all the time back when I used skins (the default map used to be oswald).