Using "Swap" (spell) when the friendly target has been targeted by a Doombringer's "Bounce" ability

This has almost lost me games at crucial moments twice now; my opponent's Doombringer (I find out in retrospect) targets one of my units with its "bounce" ability, I attempt to use "Swap" when that particular friendly unit is the closest target and therefore the unit that will be swapped, the swap animation plays except at the end, the opponent's unit is not swapped or moved at all but my unit is bounced 4 spaces from where the opponent's unit is. (I am unsure how the direction is determined, since "Swap" is supposed to put my unit where the enemy unit was and I haven't noticed any obvious pattern or if it works similarly to knockback). Is this intended? If not, please fix! It doesn't make any sense and it throws games!