Heimerdinger's Turrets: are they working as planned?

I've noticed after the new runes/masteries patch that Heimerdinger's turrets attacking an enemy champion after a successful ability use cause enemy minions to attack Heimerdinger as if he had auto-attacked the enemy champion himself. I was playing Heimer a lot before this recent patch and this had never occurred before. Is this an intentional change that wasn't mentioned in any patch notes? It makes trading pretty much a lose-lose whenever it occurs.