zenonp
At z15, the map looks perfectly correct. At z16, however, a big rectangle appears within which all land except streets appears as water. See 

https://www.openstreetmap.org/relation/2149189#map=15/-34.6594/-58.3676

https://www.openstreetmap.org/relation/2149189#map=16/-34.6594/-58.3676
