It might be a growth spurt. But it is pretty typical for a baby who started sleeping really long stretches early on to get back to nursing more often at night at some point. The more frequent waking/nursing at night is what is typical, not the long stretches.
First off, are you offering to nurse even if she is not showing signs? And what happens if you do? As I am sure you know, transitions are a big deal for babies & young kids, and for some, a really difficult time. Some babies respond to the first sight of mom after a separation by diving for the breast whether they are hungry ort not, but other children appear to need more of a warming up period before they can relax and nurse. Second, I do think it is possible they are misreading her cues. She may need comforting, she may be indicating she needs you. In her mind, mom and nursing are linked. So perhaps baby wishes to get to sleep or be comforted for some other reason, and of course she thinks of nursing/sucking as comfort. If you don't want her given more milk so close to the time you are going to arrive, which makes sense, what other forms of comfort is the dcp able to provide?but another 1-1.5 hours passed before she showed signs of being hungry and needing to nurse. To me that proves that either they are misreading her cues or she appears hungrier of her desire to suck while I'm away. What do you think?
Does your day care provide a written report of when and how much baby ate? I think if it was in writing, that may help with them following your directives more and give you a better idea of exactly what is happening there.
I think that the reason we worry about a baby not taking in enough from our non-see through breasts is because we have become a bottle feeding culture. What would really help is if bottles were not clear, and then babies would be fed until they show signs of being done instead of until they ate some preconceived notion of what is 'enough' at that moment. I am going to go out on a limb and guess that you let your older children eat as much as they want, which will sometimes be a small amount and sometimes a large amount, depending on their appetite at the time (and how much they like what they are eating) just as adults and everyone else (who eats normally) eats. Babies are the same. A normal healthy baby has lots of control over how much they eat at the breast, and thus will eat enough and not too much at the breast as long as they are nursed as much as they wish. But a baby who is being given a bottle may not have that choice, as they have a hard time controlling the flow unless the caregiver helps them do so with paced bottle feeding technique.