When gaining the djinn effect to curse one enemy at the start of the fight, it applies to all enemies. Have seen it a couple of times now. The same has been reported about blessing enemies (did not have that one yet).
As has been speculated in the mana penalty thread, that covers a related issue, it might be, that the effect is not activated once, but once per troop in the own team.
Note that certain buffs legitimately say “all enemies” instead of “a random enemy”, (e.g. Daemon offer: “Stun all enemies” + “Bless a random enemy”) so my guess is that maybe all buffs are being applied teamwide (compare Dungeon Traps) regardless of the phrasing?
Which feels like the better implementation really, but…
Quick story time. I got the genie and the choice were, good…cleanse all allies on 4 or 5 gem matches, bad…less brown gems. I didnt have any brown troops so i rolled and got the good. But when i started the match i had the cleanse but so did the enemy. Now later i got the daemon and got the bad negative status effect on plus gem matches and the enemy did not have that so i figure its a bug. How is it good if the enemy has it too
When you get the 4 or 4 gem matches cleanse on the genie
During delve run, genie blessed my team with something like Queen Beetrix last trait: cleanse all allies on 4+ matches.
This effect has also been received by all enemies through whole run.