Inconsistency in milk intake

Cheryl

Hi my baby is 8 weeks 6 days, had been bottlefeeding since birth (formula and breastmilk mix). Since last week she has been inconsistent in her milk intake, sometimes she only able to finish 40ml and at times she be able to drink finish all 90ml. And she takes 4 to 5 hours to be hungry. Once she fall asleep she will not suck anymore and the rest of the milk will have to be thrown. Have any of the babies here facing the same problem? Is this the leap stage?