One or more of the rivets on the blinker/light stalk component housing has failed. These are almost impossible to repair. You can buy after market stalks on EBay for a reasonable price. However the aftermarket ones are susceptable to breakdown in the same area, if used roughly.
Reasonably easy to replace the unit. Remove horn pad cover(Pulls off. Watch out for springs). Unscrew steering wheel nut & remove steering wheel (might need puller if unlucky) . Remove steering column covers. Undo wiring connectors to stalk. Remove stalk retaining screws & withdraw unit. Replace with new unit (reverse procedure)