I think it is a couple of things.
First their OL is really bad - they lost all 5 starters from last year.
Second, their WR's are not playing nearly as well as last year - a ton of drops (I think they said something like 39 coming into this game - that is over 6 per game)
Third, they are running a different offense this year and I think Armstrong is less comfortable with it.
FWIW, their OC from last year is now at Syracuse. Syracuse QB Shrader this year is 106-152 for 1,434 yds, 12 TD, 3 INT in 6 games. He also has 300 yds rushing on 78 rushes. Last season Shrader was 123-234, 1,445 yds, 9 TD, 4 INT in 12 games. He did rush for 781 yds last season in 12 games.