The mechanic on Divine Protector is technically working correctly.
It is how Captain Skullbeard has always worked. He creates 5 skulls, but even if those 5 skulls match to a 4x or 5s you still won’t get the extra turn if his explosions destroy the 4x/5x.
It is really annoying to have that 1 explosion when using a divine class with the weapon alongside a full team of divines, but it oddly enough makes the weapon stronger in all instances with 3 or less divines. Even 1 or 0 divines the weapon can still accumulate a decent amount of mana due to the explosion.
I think it mainly comes down to the need of having an option on all troops and all weapons to choose if a trait or perk is active at a given time.
But yes, weapons overall do need quite a balance overhaul as the upgrading system on 90% of weapons is pretty trivial with many “benefits” sometimes giving negative effects with actual good effects being locked behind getting the negative ones.