[GAMEPLAY] - Enemy Fiddlesticks Drain Summoner In Range of Own Turret, Turret Focus Does Not Change

I noticed in a game today that an enemy Fiddlesticks was able to Drain my summoner within range of an allied turret of mine, yet, the allied turret still attacked the minions instead of the enemy Fiddlesticks. I didn't anticipate this occurring so I do not have a recording. Has anyone else seen this occur, or maybe it depends on a specific summoner combination for this bug to occur? This happened at my team's inner middle turret as the outer middle turret was already down. Thanks in advance.