I have an R1200 GSA. They did not come with the euro LED signals from the factory if you're in the US. The dealer would have installed them, probably with a resistor somewhere. Your problem is that the right turn singles aren't putting enough load on the system to trigger properly.

Take one signal off at a time and connect a normal 12v lamp in with leads. That way you can isolate which end of the bike is causing the issue. Once you isolate the problem see if you can make sure both diodes on that stalk are working, they have 2 big LEDs per signal IIRCC. Look for any resistors tucked into the stalk or the bike. They may be built into the chip in the signal proper.

If you can't find any pigtailed resistor some where, you might just have to replace which ever signal is causing the issue. The front signals are the same if I recall, the rear two are different, it has to do with the way the fit onto the bike. You could also get a multimeter and test the resistances between each signal. The one the reads the lowest resistance is the likely problem child.

In the case of the bike the LEDs dont need resistors to function, they are purely there for the benefit of the central computer. So a bad load is what is likely causing the issue. The yuro bikes (assuming you're NAFTA from your English and not yuro), have different computer programming on their modules.