The relationship between brokers and lenders is being tested, after repeated moves by several non-bank providers to withdraw loan approvals from home buyers.Mortgage brokers say lenders are even marooning pre-approved borrowers after they make home purchases, forcing them to make last-minute dashes to other credit providers to ensure clients meet settlement deadlines. A NSW broker, who spoke to Banking Day on condition of anonymity, said he managed to find alternative funding for two clients in late March when their lender - a non-bank - said they would not deliver previously approved funds to settle a property transaction."We had to find another lender for the client who was put under a lot of pressure when their approval was reversed," the broker said."This one and other cases I'm aware of have created a bit of a trust problem between brokers and a couple of lenders at the moment."Similar cases involving borrowers in Victoria have also been reported by brokers - an indication that the practice is becoming widespread.The problem could intensify in coming days and weeks despite the government's ban on on-site property auctions triggered by the COVID-19 crisis.A spokesperson for the Real Estate Institute of Victoria confirmed on Wednesday that 420 properties were auctioned online last weekend with a clearance rate of 90 per cent.Pre-approved borrowers who made purchases at those auctions could be more exposed to the risk of lenders reversing lending decisions.The move by leading mortgage insurance provider QBE to suspend cover for borrowers employed in the tourism, hospitality and other industries heavily affected by the COVID-19 crisis could force some lenders to jettison more loan approved customers.While lenders might justify withdrawing approvals on responsible lending grounds, stranded borrowers stand to lose on property transactions that cannot be settled.Backing out of such transactions often means that rebuffed borrowers forego the cash deposit they stumped up for the properties they had intended to buy.