As soon as Decimator Beetles ability resolves, state-based actions are checked, and the game sees that you have both counter types on your Servant, so one +1/+1 counter and one -1/-1 counter are removed at the same time (resulting in Servant dying)
On top of its popularity, Magic Cylinder is notorious for being off-center
Two comparison points matter most
Null Brooch was one of the more dangerous artifacts to ever be printed
During your Main Phase: You can banish this card (until the next Standby Phase), and if you do, place 1 "Noble Knights of the Round Table" from your hand, Deck, or GY, face-up in your Field Zone, then you can Special Summon 1 "Artorigus" monster, or add to your hand 1 "Noble Arms" card, from your Deck or GY
With that, a whole swath of previously-errata'd cards were added to Gottlieb's to-do list. Monday's update contained the fruits of our subsequent labors