emergency room problems

so i was playing infection on high noon, and in the second round i infected 3 surviors but it said i only infected two, why did it do that and why didnt i get the achievment?
theres a video of the round in my file share.

Were you on the right map?

> Were you on the right map?

ya i was on high noon which is an anniversary map

was it in the same round?

Was it Infection? Alpha Zombies never worked for me…