I think sometimes it's a disconnect between the teacher who interprets the students understanding only from their playing [or more from their inability to play]
Then a students mistakes or bad playing is interpreted as their misunderstanding or ignorance of what is correct.
Whereas the student is thinking "Yes I know what I just did..I know it's wrong...I know what I should be trying to sound like....I'm trying to play it correctly...what I need is for you to say something about HOW to correct it and not your usual bollocks..." and so they play over what is probably you repeating yourself.
I quit my first teacher when I realised that after 3 or 4 lessons she'd said everything she was ever going to say [and there was nothing specific or detailed in it] and so by the 10th lesson it
was pointless listening to her and I started to play over her, and I could see from the look on her face she thought I was being rude. I knew my playing was sh*t, but she had nothing to offer to fix it, other than stating the obvious [i.e some aspect of the playing that was wrong, rather than 'here's how to play...']
The worst of it was that, each week, the mistakes would change, so lesson after lesson would be wasted switching from 'play it slow' to 'play the dynamics' or whatever she'd decided after 1 or 2 bars was wrong this week, without ever getting anywhere - especially when she repeated a 10 minute generic speech.
She simply couldn't understand that the mistakes weren't ignorance of making a mistake and nor was saying "your tempo is wrong" or going into a long diatribe about how important tempo was, "especially when you play with other musicians" as though she imagined I was playing like a **** deliberately, rather than because I was completely and utterly ignorant of what I could do to fix the mistake. Had she said something about about how to fix it I'd have closed the lid of the piano or stood up and let her play.
So bear that in mind, if you've a 5 year waiting list and you're on your 3rd internationally acclaimed book, perhaps they're just being rude, but OTOH, perhaps it's just a politer way of them criticising what you're saying, without saying it outright?