Did the dollar general coupon policy change?

I’ve done the dollar general $5 off $25 deal twice without any problems. I haven’t been in a couple of weeks but I wanted to go today and I was checking everything in the app and the coupon won’t apply even though my total before coupons was $28. But when I add more stuff to my cart to get the total close to $29 or $30 it does. Is this just a glitch with my app or did they change the minimum?