cerberus fighter base

Playing Mass Effect 3 for the first time through the Legendary Edition on PC. I have been using a guide that has an optimal mission order and it states that N7: Cerberus Fighter Base comes directly after Priority: Tuchunka–as well, several wikis also support this data. But when I completed Tuchunka, I received N7: Communications Hub via Specialist Traynor–a mission that shouldn't appear until after Priority: Thessia.

What happened? Why did I not get the correct N7 mission at the supposed right time? I suppose that having missions out of order shouldn't affect anything too drastically but it feels wrong that multiple sources say Cerberus Fighter Base should have opened up but it didn't....

Any help is greatly appreciated.