Bajaj Finance’s shares have long traded on the assumption that flawless execution can outlast any economic cycle. That faith is now being tested by a leadership gap the company thought might never open because of its meticulous planning.The abrupt resignation of Anup Kumar Saha, the hand-picked successor to Rajeev Jain, leaves India’s largest non-bank lender scrambling at precisely the wrong time. Saha was groomed internally for eight years and lasted just four months in the top job. He is expected to take up the chief executive role at IndusInd Bank, a competitor in retail lending. The result: Jain, who had stepped back to become executive vice-chairman, will now be vice chairman and managing director.