Brian, our front turn signals are real bad about corroding behind the bulb. Water comes down the stalk where the wires go in and pools up behind the bulb in the ass end of the socket. The contacts and little springs back there will break. If they do it's at best the same effect as a burned out bulb. At worst it's a little short.
If nothing else that's easy to check makes any difference then yank the fairing and unplug the connector that feeds the turn signals. Six wire plug to the left of the radio with purple, blue and black wires. If taking the front signal housings out of the loops solves or changes what you're seeing you've probably stumbled on to the problem.
Don I took the front turn signals apart yesterday. A few teaspoons of water came out from behind the bulb. Cleaned all terminals, used dialectric grease to re-install and all works except when the motor RPM's increase.
Found at the 6 pin connector it had come loose frpm the cross member that goes to the speaker. It is held in place by a little pin. The connector was rubbing on the bracket and the blue and black wire going to the left turn signal were touching the bracket and had worn the insulation off the wires. Each time the motor RPM's were increased the wires would rub on the bracket causing the problem.
Fixed them and now today head for MB and will see if that takes care of everything.
Oh yea we took every connection apart under the fairing, cleaned them with electronic cleaner, blew off with compressed air an re-installed using dialectric grease

time consuming but hopefully worth it.