I’ll start off with this statement: I’m pretty sure this isn’t a bug, but I’d like to think this is at least an oversight.
Though I frankly think Reno is too OP, I do think and believe that Reno wasn’t intended to prevent a card from doing it’s abilities that don’t summon minons. Yes, I get it. The void from Sargeras summons minions at the end of the turns, but on the other hand it’s not like you can code for those minions to just not spawn. Same goes with summoning the two 6/6 demons. However; there are two other abilities of Sargeras. One is To The Void - which does require the void to actually be spawned to even use. The other is let the imps have Taunt and 2 health. Again - they dont need to spawn or they just disappear/die while Reno is active. It’s tough enough as is as a Warlock main, but Sargeras needs to change with it’s void being immune to Reno, Reno to effect both players with 1 minion / 1 location (I believe that’s what Void, etc etc is), or Sargeras being allowed to use To the Void without the need of the Void to actually be able to realistically react to a Reno play when a player (such as a druid) has their side of the board filled up with minions, go face, then it’s your turn and you’re just staring at death the next turn because you can’t play Sargeras or anything to clear the board UNLESS you just happen to have Twisting Nether in your deck/hand.