March 2017
I have had the Zombomb die within 3 seconds after the round starts on Aqua Center on several occasions. I haven't had this problem on other locations that I recall. There is no way to protect it in that short of time. It seems he spawns either nearly dead or in the same point as the plants.
December 2018
I have the same issue, still one year on from this post. I think it only happens when you choose garden A.