Hello.
Check this webpage
https://www.openstreetmap.org/way/1423988086/history#map=19/31.740194/130.709591
You mapped 1 large building with 2 small ones on the left side.
These 2 mappings are the sidewall of the same building. Not to be mapped as individual buildings. Just map over the rooflines and move the whole to its footprint.
Best regards
