Ballistic Enchantment seems to have a limit of 3 stacks whether it's from heroes or non-hero units. The stacks also seem to be unable to be built/overridden until the previous stacks expire first.
So if you have 3 stacks built up from creeps, you cannot build any (higher damage) hero stacks until the old stacks expire first. Seems unintentional as it punishes players for maximizing Ballistic stacks on creeps.
The tooltip is also misleading because it does not mention the 3 stack limit, and instead only mentions an incorrect '8 Non-Hero stack limit'.
So if you have 3 stacks built up from creeps, you cannot build any (higher damage) hero stacks until the old stacks expire first. Seems unintentional as it punishes players for maximizing Ballistic stacks on creeps.
The tooltip is also misleading because it does not mention the 3 stack limit, and instead only mentions an incorrect '8 Non-Hero stack limit'.