Hearthstone Mercenaries - Speed Bug

Situation:
Mr. Bigglesworth ability Feline Fine (Speed 9) targeting friendly Sylvanas Windrunner vs Aranna Starseeker ability Felodic Intonement (Speed 9) targeting enemy Sylvanas Windrunner (with Chromie Change of Timeline active)

11 times in a row now (10 x while I was the Aranna player and once as the Bigglesworth player) my opponent’s ability has gone first. This is supposed to be a coin-flip but obviously is not. The odds of this happening randomly is 1 in 1024.

Please explain.