Zilliax Deluxe with pylon module. When you magnetize a minion it doesn’t correctly add the magnetized minions buffed attack, instead it treats it as if it wasn’t buffed when it magnetizes into Zilliax, but the health is increased as if the 1+1+ buff was in effect.
For example, have a 3/5 zilliax on board and then play a 1/1 sparkbot, once it magnetizes zilliax comes out a 4/7.
Edit: This also happens if you magnetize onto another minion, the health after magnetize is either 1 higher than it should be (the zilliax buff should not apply to magnetized minions)_ or the attack is 1 lower than it should be (if the buff should apply to magnetize)