Hi,
You have removed the building tag from https://www.openstreetmap.org/way/488753974 and replaced it with leisure=horse_riding. Therefore the building is no longer renderes as a building. The horse_riding tag is actually not intended for buildings, but for the entire area of the equestrian center. See
https://wiki.openstreetmap.org/wiki/Tag%3Aleisure%3Dhorse_riding.
The riding centre can be mapped as a separate object (area or node), examples: https://www.openstreetmap.org/way/703036885#map=18/53.092383/6.694458&layers=P, https://www.openstreetmap.org/node/8586932566#map=18/52.718887/6.143715&layers=P

(There was a similar discussion one year ago: https://www.openstreetmap.org/changeset/142592518)