Exact same thing is happening in our house. My little sleeping bubba has decided to wake up two extra times at night.

He usually goes to sleep about 6.30pm-7.00pm and sleeps until 4.00am, but now he wakes about midnight and also sometimes about 2.30ish. He feeds and is straight back to sleep also. I've noticed these are really long fees, empties both breasts and after a burp or two is asleeps quicksmart. I don't think your DD needs solids, I'd say it is just a stage and to stick with what you're doing and before long she will be more settled.

HTH
Spring