Invulnerable Rek'Sai tunnel [GAMEPLAY]

I was playing Rek'Sai top lane last night against a Vlad and one of my tunnels glitched out in the middle of the lane. No matter how many times Vlad or his team mates tried to destroy it, they couldn't. It also didn't matter how long they stood on top of one of the entrances. Additionally, it didn't count towards one of my active tunnels, and had no timer ticking down to where it would despawn like a normal tunnel. All the while I could still use it whenever I pleased. Even ult to it. I'm not sure if this has been brought up before but I just thought I should mention it. I have absolutely no idea how it happened or how I would get it to happen again.