Hi,
You have removed the building tag from https://www.openstreetmap.org/way/612258883 and replaced it with leisure=horse_riding. Therefore the building is no longer rendered as a building. The tag leisure=horse_riding is actually not intended for buildings, but for the entire area of the equestrian center. See
https://wiki.openstreetmap.org/wiki/Tag:leisure=horse_riding.
The riding centre can better be mapped separately from the building (area or node), example: https://www.openstreetmap.org/way/97438164