I have a theory about why certain objectives sometimes fails to update in certain circumstances, but i need more data to support this theory.
THe theory is:
Lets say you have a team made up of 2 players They are in a multi-stage mission, and one of them has a slower computer than the other, leading him to spend more time in-transit between zones.(the game calls this Map Moving.)
At a point in this mission NPC A is standing just off the spawn point, leading player A to talk to the NPC just after zoning in, while player B is still "Map Moving" My theory is that the objective-tracking system will fail to update Player B's objectives. Everything will appear to work in the on-screen objectives, but as soon as another major objective comes around, checking your mission log will show that it has in fact not updated.
So i need help from players who are doing Infected. Either test this by making sure noone talks to the first NPC until all have materialized and report your success here(indirectly supporting my theory), or try to trigger this bug intentionally by having someone talk to the NPC and chose the green option while some player is in-transit between the first part and the second part of the mission, and report you degree of success here.
I have full understanding if noone wants to help, i know all too well the frustration you feel when this mission bugs and i cant really expect people to knowingly attempt to bug the mission for them. But if you manage to dodge this bug by making sure all zone in fully prior to updating the first objective, i would also be very interested to hear your data.
We actually are running with this theory, checking out whether this is the case for many missions not giving credit properly. Stay tuned!
If a group of players does want to test this out, though, it would be really fantastic. Just make sure to include as much information as you can, take lots of screenshots as you go (of your mission trackers and captain's logs), and keep track of exactly at which points everyone loaded in, did objectives, etc. I'm hoping that with enough information, we can figure this out and reproduce it every time.