Dennis H.wrote a review of Shimano Dura-Ace ST-R9100 11-Speed STI Shifters on June 28, 2019
After about a year, the left lever refuses to shift to the small ring. There is a tiny arm under the lever that is supposed to return to center after shifting to the big ring. It hangs up & does not return to center. Because of that, when you try to shift to the small ring, nothing happens unless you manually put that small arm back to center. This is very irritating, especially since Competitive Cyclist & Shimano keep telling me to contact the other for help. To get Shimano to help, I need to send the shifter back to them for 3 weeks!