I was doing Solo Master Lost Sectors on Europa today and thought the drop rate for exotics felt a little low. I did 10 runs and got 2 pieces. Afterwards I checked my triumphs and saw the following: Solo Lost Sector Mastery: 5 Lost Sector Mastery: 10 I am wondering whether the solo runs sometimes aren't counted as solo? I definitely never had a fireteam. That could also explain the low drop rate.