I'm pretty sure I know what's causing this. It has to do with the behavior changes made in 5.2.
At 2 or 3 soldiers, it takes the soldier nearest to the target position and moved it to the left of the target or at the target, respectively.
But if you spawn the soldiers at the EXACT same location, the game only recognizes one soldier, and moves it accordingly.
Spawning 2 or 3 soldiers in different locations makes Q behave properly every time. Spawning 2 or 3 soldiers in the exact location causes this glitch to happen every time.
Take Soldiers A, B, C, spawned in that order.
A and B are spawned on X.
C is spawned on Y.
C and B will move, but A will not. (We know it's A because it disappears first).
A, B, and C are all spawned in X.
Only C will move. (A and B disappear at X)
Not game-breaking whatsoever. If you don't have the mechanical instinct to move your mouse between soldier spawns for attacks or movement or other actions, you have much bigger issues to worry about, and probably shouldn't be playing Azir in the first place.