OpenStreetMap

looks fine to me? maybe i'm lacking in experience

The imagery has changed since I initially commented on this, and the Bing view is so oblique as to be almost useless. However, using the best available imagery on iD, Esri World Imagery (Clarity) Beta, and compensating of the offset of the water feature, the outline of the main building is still 8-10m South East of my best estimate of the ground level boundary of the building.

On the other hand, most of the points on the feature haven't been modified since before my initial comment, and I cannot justify a 30m offset, so I'[m wondering if I failed to notice the view was extremely oblique and used the top as the reference (without having seen the current Bing view, I could easily make that mistake on the current Esri Clarity view

I use Singapore OneMap layer as reference on iD. Is official/from government so that layer should be more accurate than satellite imagery