These aren't wrong - you're only copying mesh data with copymesh, not entity brush properties or animations so, again, this is expected behaviour.
If you are subsequently using addmesh then note that it combines surfaces which share the same brush properties - I'm guessing this is why the copy only has 1 surfaces instead of 5.
If you are subsequently using addmesh then note that it combines surfaces which share the same brush properties - I'm guessing this is why the copy only has 1 surfaces instead of 5.