Does not appear any more in F4 map. We have tried all kinds of tags and waited.
This one does
And this is how it looks =
The reed has been cut recently.
I do not know the purpose of the reed.
Without even looking at the other elements, the OSM 2D rendering is not the same either, so I’m guessing you have another element in the same spot.
Likely this : https://www.openstreetmap.org/relation/7531198 which indicates it’s grass.
I just saw that the pond does not appear in osmand.
The multipolygon relation must be the cause.
I deleted the relation.
Solved, without side effects, I think.