Present perfect continous
I got a question from my today's class. There's a sentence said, 'She has been getting better during the summer.' which I found that I hardly agreed with this. In my opinion, all the present perfect should be an impact or a connection as the speaker believed from the past to the moment it is mentioned. 'During the summer' is a particular period of time which also unidentified without other details. However, two of my teachers that I consulted gave me the same answer, which they thought the sentence was correct.
No matter you think this sentence is grammatically correct or not, please leave your comments.Thanks for your opinions on this question. Actually, that's what I was going to say, which it should be considered a correct way to express if it happens in the summer. But the thing is, this sentence came out from a grammar practice which letting us use some of the events to connect with a time phrase. I couldn't agree this was a fairly correct answer.