Title says it all. I was running an Elite Faction Mission, found the solider and got the info on the computer, went to the second location and then my game just started to fry. At first the game wouldn't let me out of combat, I mean I literally ran for over 2.5km to the nearest camp (with no one on my radar for half of the way) and was still in combat by the time I arrived. The robots didn't seem to lose interest in a normal amount of time either, they just kept following me, knowing exactly where I was even when I was out of sight for ages; in the end I swam over a large body of water where they couldn't follow. When getting to the camp and killing any remaining enemies around me I pulled out my chopper and flew back to the place, aimed at the ground and my rockets just shot into the sky.

After all this I decided it was best to restart my game, I've ran Elite Faction Missions from day 1 and had never encountered enemies that acted that relentlessly, plus with my Heli now glitched I thought it was best as something was clearly wrong. So I do that and re-login. First thing I see is that the mission has vanished off my map, I check the page and it says its unavailable but I can press square to restart (with every other mission it restarts you at the last checkpoint). So I do that, respawn in and I'm right back at the very start of the mission, where I started when I first logged in.

Frustrating isn't even the word, I was genuinely pissed. I understand games have bugs at launch and need patching but surely it would of crossed someone's mind that there should be checkpoints in all missions incase someone has to restart because of one of these bugs?

TL;DR: My game glitched out and I ended up losing around 2 hours of progress because of a bunch of annoying glitches in this game and the lack of intuition to add checkpoints to Elite Faction Missions knowing the state of these glitches.