Hi,
You have removed the building tag from https://www.openstreetmap.org/way/273996583, Now it is no longer rendered as a building. Isn't it a building? The tag leisure=horse_riding should be used for the whole facility and not for some building, compare
https://wiki.openstreetmap.org/wiki/Tag:leisure%3Dhorse_riding
https://www.openstreetmap.org/way/442937025
https://www.openstreetmap.org/node/8755586716