Is it OP that teleport can be used on Zac's respawn blobs?

For those of you who don't know, teleport can be used on any of the 4 blobs that Zac splits into when his passive activates. This essentially Zhonya's him for the duration of the teleport, which is 4.5 seconds.

I'm not sure if being able to teleport to Zac's respawn blobs is OP or not. Even though it pauses his respawn, 4.5 seconds is a lot of time for the rest of the team to get into position. It also means someone who defeated Zac, but only has a sliver of health left, has to leave and lose the kill because the teleporting teammate will finish them off. What do you think?

Edit: Why do some people feel the need to downvote this? I'm asking a question, relax.