There are many spells and traits in the game that target a random enemy with a particular effect. For example, Wulfgarok’s spell devours a random enemy if its damage killed its target.
These effects can and often do target an enemy that is immune to the effect. This is fine, and expected.
Charm, however, is different. Instead of picking an entirely random enemy, it picks only from enemies that are not immune. There are 3 ways to be “immune” to Charm.
1- Having Bless status
2 - Having the Indestructible trait. This is currently exclusive to level 30 Immortals
3 - Having an Attack score of zero, whether through Entangle or any other reason
I didn’t raise this as a bug, as it appears to be intentional. Why does random Charm get this special treatment when other effects do not?
In fact having immunity to Charm makes a troop more likely to be damaged by it, since its neighbours will be randomly charmed rather than resisting the effect itself. This greatly diminishes the value of immunity to Charm, making it not such a great level 30 perk for immortals.
As an example, in Tower of Doom today, I had potion of bless and was fighting the double Lamia team. If they cast while my whole team is blessed, the message “No targets available” appears, indicating immune enemies are excluded by their random charm. If one of my troops loses Bless, it gets “randomly” targeted every time. Is this fair?