Yes. In the multi-calendar view all private notes, blocked days and Airbnb reservations have been completely wiped from display from Sept. 5 - Oct. 5. Starting Oct. 6, all of this data is still showing and before Sept. 5 back you can see the historical info. For some reason exactly one month of this data has been completely wiped from the multi-calendar. I'm not sure if the same period of time is involved in all cases.
Now, if you look at an individual listing's calendar, all of this information is still there. For some reason it's just the multi-calendar that has evidently been corrupted between Sept. 5 - Oct. 5.
I have talked to 3 different hosts, all of which are having the same problem with the multi-calendar view in their accounts.