Thanks for the post - hopefully we can figure out why you're seeing this. There is no special logic that kicks in for goal-to-go situations, so it should be pulling completely from your game plan. Looking in the DB I see a pretty balanced spread:
PLAYS INSIDE OPPONENT'S 5
31% Outside Run
26% Inside Run
28% Short Pass
13% Medium Pass
2% Long Pass
In your game planning screen, if you click on "View Plays" for that last quadrant (most likely inside the 5 will be considered "short" unless you're having a really, really bad day offensively, in which case you probably won't be inside the 5 very often) you should see the weight for each play in that situation - are your passing plays weighted close to the running plays? Be sure to look at your personnel as well when making adjustments - if you load the recommended personnel, the AI will put more emphasis on heavy personnel which will tilt the play calls toward the running plays.