Could be the timing but I suspect moreso that she is holding out for solids... at this age, you really should be limiting solids when it has an impact on her milk intake. At her age, you do want her to stay at 24 ozs/day (just over 700mls).
When did she start solids? She is very young to have 3 "meals" a day. Most babies at this age are having solids just once a day as a meal (generally breakfast) and then milk feeds at all other times. After a good 4-6 weeks of a single meal, add in a lunch offering, then in another month or two (closer to 8/9 months) add in the dinner meal. Generally by this point, most move to 3 bottles a day.
Also, a "meal" is usually around 2-3 tbsp's at this age
The biggest concern with so much solids at this age is two-fold: she won't get the proper nutrition that she would from formula (it has more in terms of fat/calories than solids do), and the other big concern - constipation. It's unlikely that she will take enough water from a sippy to balance out the large volume of solids she is having.
Overall, I would limit solids for a bit and see if he milk intake goes back up. Many babies (mine included) exhibit this behaviour when solids are fairly new and interesting