Act of Treason + replacing creatures = your creatures disappearing

Nathanyel

Turn 11 (me): I have Smuggler's Copter (6/6) and Consulate Dreadnought (10/10) on my side of the board; my opponent has Aradara Express (5/5) and Consulate Dreadnought (8/8) on theirs.

Turn 12 (them): Opponent casts Ballista Charger (7/7).

Turn 13 (me): I cast Fateful Showdown, destroying Ballista Charger, then Act of Treason x2, so I now control 4 creatures: Smuggler's Copter and Consulate Dreadnought (mine) plus Aradara Express and Consulate Dreadnought (opponent's). I then cast Smuggler's Copter...but instead of reinforcing my Copter (as it should have), it wanted to know what I wanted to replace! I chose Smuggler's Copter (weaker of my two), thinking maybe it would reinforce after all...but no. What happened was it replaced my original Copter all right...and my 10/10 Dreadnought DISAPPEARED completely! (I now have three creatures: a Smuggler's Copter of mine, and my opponent's two Treasonous creatures.) Having earned an extra swap, I now cast Skysovereign...and was obliged to replace my Copter...even though only ONE of the creatures I controlled was mine. So, when the turn ended, instead of having three creatures—a 10/10 Dreadnought, a 12/12 Copter, and a 12/12 Skysovereign—I only had one, the Skysovereign.

i understand that you can only have three of your own creatures in play at one time, and can only control four creatures w/the effect of cards like Act of Treason, but that still doesn't excuse Copter from replacing instead of reinforcing (when both were mine), and ESPECIALLY not the complete disappearance of my Dreadnought!

Clearly, until this apparent bug is fixed—which removes one of your creatures if you try to summon while controlling 4 creatures due to Act of Treason and its ilk—I will need to always summon BEFORE casting Act of Treason...which is annoying b/c you don't always know how much mana you will end up getting due to cascade until after you make your first match.