As mentioned in my post about game 2, I had the ball on my opponent's 1 yard line on first down with a 6-0 lead my team lines up in Shotgun 5 Wide Parallel Slants, a short pass, while having running designated heavily favored (51+%) in the situation. I had available multiple run heavy geared offenses with adequate amount of plays weighted towards each offense.
https://usflwfl.myfootballnow.com/gamecenter/view/94#17071

I checked my rules and have nothing. I checked my Misc thinking the Hurry-up could some how affect it, but the HU slider is only for the 4th quarter. So how did this happen and how can I prevent it from happening again? Or is this just another "Ooops, my AI bad"

I'm not sure. But if running was favored 51% as you said, then there is still a chance it won't be a run play. I think sometimes plays are affected by the coaches as well, but don't quote me on this.

You could probably just change something like that from happening again by making gameplan rules.

When you say 'heavily favored' towards the run, what percentage are you talking about? If you have it set to 80% run, that means, on average, 1 out of every 5 plays will be a pass. The AI doesn't take situation into consideration like you or I would.

If you want it to run 100% of the time, you have to either set the situational slider to just run, (which you can only set for the 0-25 yd line, the disadvantage,) or set a rule to run 100% of the time from, say, the 0-5 yd line, (which is more complicated.)

From what I can see, it's just the AI doing what it is told...