Baby suddenly stop taking bottle?

Our LO is 7mo and was exclusively breastfed. It took a long time to find a bottle that she liked but finally we did. I went back to work when she was 5 mo and the first month or so was fine. She had no trouble taking the bottle from us or the nanny. According to the log our nanny kept, she drank 20 oz of breastmilk very consistently every day. Our nanny suddenly quit so the past week our parents have been covering and she has very little interest in the bottle. She drinks maybe 2 ounces and then pushes it away. So she’s taking closer to 10 oz with a lot of struggle. She’s nursing completely fine for the same amount of time she always did.

Now, maybe our last nanny was full of shit and saying she drank 20 oz, but since the total about varied bottle by bottle (i.e., sometimes 5 oz, sometimes 7, sometimes 3) I don’t think she was making it up just bc that’s 20 oz is I happened to prepare. It would have been a lot of effort to totally make up her feeding log and I don’t see why someone would do that.

Anyone else’s babes go through a period of drinking less? I suppose it could have been a growth spurt but that would have been like a 3 week growth spurt.

Any thoughts are appreciated because I’m very worried she’s not drinking enough!