Hidden legal risks in Chandigarh property

What specific RERA red flags should I actually look for when checking projects in Mohali or New Chandigarh? Done with renting, I'm finally investing in a 3BHK, maybe Aerocity. Beyond RERA registration, what crucial title verification steps do people often miss? ₹1.5 Cr is huge. Any real experiences with builder legal track records or delayed OCs here?