For this lucky brifter it was a brush with death. I may have noted before that a failing shift wire can cause irreparable brain damage to brifters, particularly Shimano's. Since Campy shifters can be completely disassembled, fragments of a damaged shift cable could probably be removed. I'm betting SRAM shrouds the interior of their modern horrors in mystery similarly to Shimano, but I haven't dealt with enough of it to say for sure.
All three major suppliers of brifters now route the shift cable housing under the tape. While that gives a lovely clean look to the bars it makes checking the condition of the cables inside the shifter harder because you can't get a lot of slack by popping the housings out of the frame stops. Similarly it is difficult to check whether the ferrules on the linear-wire housing are failing, which is a common cause of erratic shifting. Linear housing wires can also push into the brains of the shifter and jam things completely.
Fortunately for this rider, his shifters have external routing. He noticed a sudden decline in shifting performance and brought the bike right in.