Well, it looks like two buildings. The right-hand part is obviously newly built (see photo). Here in the Netherlands, all buildings are registered with the BAG, the Dutch land registry office. 
The data is regularly synchronized with OpenStreetMap. Unfortunately, dividing it into two buildings would only result in the building (way 254136054) being automatically saved in OpenStreetMap again.
I took the liberty of dividing the building into two building parts.
This is a compromise suggestion. Are you satisfied with this?