When using camouflage mount on workhorse and it dies it doesn’t summon the two ponies it only summons the chameleon with the special affect. The two ponies are missing from the death rattle.
In the same game I’ve just played camouflage mount on 2 Workhorses and both correctly summoned their 2 ponies + the chameleon
Are you sure you did not play the spell on a pony ? Your workhorse didn’t get silenced before you played the spell on it ?