So there was a vague blue post a week ago about garrison invasions stating you needed to piss off a certain faction by killing them a lot. This is true but it seems like some people even after hours of grinding the level 100 mobs that are required to initiate an invasion are not getting them to occur. Myself personally I skipped the lvl 92 invasion and I believe that glitches the 100 version from happening. I was farming council rep and went all the way upto exalted without getting an invasion, than I helped someone else and my invasion quests showed up. The solution is to get invited to an invasion that someone else is having. Once you participate in someone else's invasion this glitch goes away and you are able to get your own invasions. The best way that I've found to do this is by farming rep and having someone in that group bring you along, or ask a guildie or friend. I know this has caused a lot if confusion for people so I hope this helps. On a side note id like to point out there are 6 diff factions that can invade you. You can be rewarded with an epic loot bag once per week from each type of invasion, so 6 total epic loot bags per week