Let's hope it's not a cpu issue? I have seen a 899 with an indicator problem, owner thought it was simply a globe.
Unaware of the bus system and low voltage led turn lamps, it was diagnosed as the cpu, it only affected the right front indicator, the bike was just out of warranty and cost the man around 1000 USD to get sorted. (1 x cpu later)
The break lights and turn signals on the 1299 use small delicate male/ female plugs and they do go in very firm, under the tail section. My concern with this was the long wires when I shortened the tail to bring my number plate into the same picture as my bike, number plate holder houses the turn signal and plate illumination, instead of cutting the wires and re fitting the plugs I retained the Oem plugs and managed to push back the extra wiring.
The system is polarity concious so do check carefully when checking although the Oem plugs are a one way fit only, but certainly not quality plugs, let's hope your have just vibrated lose?