Was also stuck at 60%. I was wearing just two pieces of armor until I realized what the quest was, change to have all 5, also put on emblem and now no progress being made... switched back to original build, after one match, now at 90%. Not sure if that fixed it or not.. I was also put into a match that was already started when I came in, also it was a new map? The next game was on a map on Nessus, and it finished out the quest.. so not sure if there was a specific piece of gear that glitched? The emblem I put on was pretty old, felwinter.. the gear I was wearing was all fairly new though. I don't know maybe swap some stuff around, or hope that it gets fixed.