This is typical!
Babies are like that.
Some ppl would say you have to train them.
But what I found that works, and with a lot of advice from mothers with 7 kids, that you feed on demand. Just as you would like a snack one day at a certain time, you may not want that again at that same time the next day.
Many babies LOVE to eat at night every two to three hours even when they are as old as two years!
You could try feeding your baby something solid before bed to fill the baby's tummy.