The Ballphin Palace only spawns one ballphin when built.
The naturally occuring ones spawn many.
And the ballphins run far, far away follow the sting rays and never come back, I have to travel about 5 screens away to kill them for them to respawn and do the same thing (even though there are no sting rays where the palace is).
Steps to Reproduce
1. Build a ballphin palace some distance away from a stink ray spawner.
This issue has not been confirmed by a developer yet.