In September, Shimano issued a recall of 11-speed Ultegra and Dura-Ace cranksets produced before July 2019, due to more than 4,500 reports of cranks breaking, sometimes resulting in rider injury. 

For details on the recall and crank inspection information, see:

https://bike.shimano.com/en-US/information/customer-services/corrective-actions/11-speed-hollowtech-ii-crankset-recall-notice.html

and