Hello, Mate!
Please note that only events included in the Booking.com export link are being imported to the Hotel Booking calendar. This means if those blocks are not included in the export link, they will not be imported to your Hotel Booking calendar and you will need to block the dates in question manually using Booking Rules ->Block accommodation option.
You may open the export link in the address bar in order to open/download the .ics file and check whether those blocks are in the link.
Regards,
Andre