We personally feel that it is settlement due to excessive building works and it being built on a hill. However it will need repairing properly and I do not think that they will work on it for at least 6 months to a year to allow the property to settle. The steel girders wont rust overnight, in fact they have probably already been exposed to the elements during works. But if you are worried you could employ a structural engineer to survey the property and write a report.
There will be settlement cracks appearing in all blocks due to movement and temperature change (thermal movement), we noticed cracks appearing in blocks 11, 12 and 5, but it is not cause for concern... or should I say in our opinion it is not immediate cause for concern