Seems like the hit boxes on zeds are unusually small on the experimental servers. The fire axe is pretty much useless, the splitting axe is ok but it is hard to connect for a hit.
I was in the Tent City at Balota and in front of the wooden floored tents that run parallel to the road. A hopper attacked me, I killed it, went into the tent to bandage when another hopper came in to attack me, I killed that one too, went to bandage and right in front of me, exactly where I had killed the first two hoppers another zed spawned, I killed it and ran around the corner to bandage. Another Zed did not spawn at that spot.