I think you are right. Worley also said he's used to throwing to the receivers in practice. He said they may be more tired during a long practice than they are in a game. Meaning, North was running routes faster than Worley realized.
Who knows really, but it's not unexpected given we're breaking in a new QB and new WRs.
My baseline expectation is that we'll see this tighten up over the next few weeks. Of course, those results will be skewed by the fact that we will be playing some elite secondaries during that stretch (Oregon, Florida).
Fun times.