Zz'rot taking towers without minion wave

I noticed something when I was playing with the new Zz'rot portal the other day

I had set up my portal near mid with a massive minion wave backing it up in an attempt to try to take the tower, I got some damage off but the mid laner showed up quickly to take the wave down, after this they followed me bot lane to help with a fight without clearing the portal. After the fight ended I ran by the portal I had placed only to notice that the portals minions were spawning, running to the turret, tanking a tower shot and still dealing their damage to the turret.

I tested this again by placing my next one near top lanes middle turret, which had taken no damage. I observed the same thing; every single minion spawned by the portal tanked the turret shot and got its damage off. Leaving the portal alone i then roamed around mid/bot trying to create a ton of pressure so my portal could do its work without being cleared, when I came back to check after my portal expired, the turret had lost half of its health without any minion intervention whatsoever

Am I foolish to think that this is in no way intended? It seems like the ability to consistently damage a turret with no help from minions whatsoever would be pretty unhealthy, it just seems odd that no one else would have noticed this by now. I do not remember the old zzrot being able to do anything like this.