Hydralisk evolution mission not appearing when expected

Copied over from Campaign Discussion:

I completed the missions in the following order:
Char-Zerus-Kaldir-Space … currently going through Skygeirr.
I completed all of the evolution missions as they became available (Zergling, Baneling, Roach, Swarm Host).

Prior to Skygeirr, I had not completed, nor had the option to complete the hydralisk evolution mission.

The Hydralisk evolution mission finally appeared after completing Skygeirr 1: Infested.

I expected to have access to the hydralisk evolution mission right after getting the hydralisk in Kaldir: Shoot the messenger, since I had already completed Zerus: Supreme, which triggers the hydralisk evolution mission.

Theory: you unlock the hydralisk evolution mission 4 missions after unlocking the hydralisk.
For my case, I did Shoot the Messenger (0) + Enemy Within (1) + Waking the Ancient (2) + The Crucible (3) + Supreme (4), and it fit also fit the theory that Supreme unlock it.
For your case, it would be Shoot the Messenger (0) + Enemy Within (1) + With Friends Like These… (2) + Conviction (3) + Infested (4).

It fit so far, but need confirmation, once again, it’s only a theory to try to forcefully fit the facts.

I confirm this. I did the same order that @GhostDragon did and, as you say, the reward for Infested is the Hydralisk evolution mission.