There are times when my baby seems hungry while I'm nursing her. She pulls off and starts crying but will continue to feed when I put her back on.
It could be that she is expecting instant milk flow and gets frustrated when its not let-down yet. Sometimes babies fuss and we don't know why. It could be that the milk is flowing and she is getting too much in one go and pulls off to try to manage the flow. None of this is abnormal--it is good that she latches back on and nurses when you relatch. If you have noticed she does it at the beginning before let-down, you can hand express just a little bit so it is already letting down and she can latch on and drink right away. If it is after let down, she may need a burp or to take a little rest. If it persists and you are worried about it, an in person consultation with an IBCLC would help so she can assess the latch and see if there is something else that is bothering baby.
Gina Ciagne, CLC