Outstanding building orders in Mosman can affect a purchase in two ways: directly, if the property you are buying is subject to an order, and indirectly, if a neighbouring property has an unresolved order that creates a safety or amenity issue. The suburb-level data below gives you the broader context; the Section 10.7 certificate for a specific property gives you the definitive answer for that lot.
For buyers of freestanding houses in Mosman, building orders are rarely a concern unless the property itself has an order. They are more common in strata buildings. For unit buyers, check whether any building orders relate to the common property of the strata scheme, as owners corporations can pass special levies to fund rectification works that are disclosed in the orders but not always in the strata report financials.