Sorry, back again.
I am sorry to say, but lots of buildings are wrongly mapped.
Flat pieces of land. Mapped as a building.
From a high building you mapped the building itself in 2 pieces, the siding as 2 pieces and the shadow of it.
On this page you can see what I had to adjust.
https://overpass-api.de/achavi/?changeset=132997736
About mapping of tall apartment blocks

Mapping of tall buildings differs from standard buildings. Because the imagery is taken at an angle, you see both the rooflines and also the side of a building. 
How do you map such a building?
Map over the rooflines and lastly slide the mapped building to the footprint.
Please adjust wrong positioned buildings as well
This video shows how that is done.

https://drive.google.com/file/d/1V5-bADsYiffCD9bo6l64YOdTvmKqMGry/view?usp=share_link

And.... don't forget to square each rectangular building.
I am not blaming you, but try to explain what went wrong.
Best regards and keep mapping