So my gf (Kokoai) and I (Bit-Byter) were working on missions like we do any other day. While she does not have actual access to the missions I am on yet, the increased heat and crown drop are precious to her. We were working on the last mission I had in tier 7 "Spark and Roar". We were on the last floor (an arena) and finally made it to the last section of that arena. However, after clearing two groups of enemies a weird lag spike hit the both of us (We aren't on the same internet so for a single lag spike to hit both of us is odd). We both saw enemies frozen in place, I actually saw a lumber waking in a straight line on thin air. The spike resolved itself quickly and the enemies moved again. For a second. Then they froze. Unable to do anything while me and Kokoai killed them. They showed their idle animations and death animations just fine. But they didn't move. And after they had died the bodies were still there. While the two of us couldn't see them, our guns still made contact, and we couldn't walk where they had died. We waited several minutes for this to catch up, but it showed no signs of it simply being lag.
The two of us are both using up to date versions of windows 7, as well as running the game through steam. I have images if needed, though they aren't that helpful given it's hard to time a snapshot of when your firo driver bullet actually splits when using print screen to capture the image.
we had something like this happen once in FSC. We called a GM, as soon as the GM came all the monsters exploded and coins rained from the sky.
Moral of the story: Call a GM from the support portal.