It's possible that a server-side texture pack changes
item tile/image definitions in order to implement
the overrides for a server-side texture pack (e.g.
using the custom grass side texture that the
"improved" pack uses) which would cause issues
with vanilla textures.
Pull in the auto-generated overrides from the
vanilla game as well as the textures, to force all
vanilla node definitions to their defaults.
Note that this does not cover mods, but currently
mod support in texturepacks is itself nearly
nonexistent, so this shouldn't be a problem yet.
