So I can't make sense of this. Front turn signals are working, however the rear signals aren't. The tail light works but not the brake light. When the turn signals are activated the tail and license plate lights flash. WTF?
I checked all the bulbs and they are all good. I even went the extra mile and changed them all, but no change.
HHHHEEEEELLLLLLPPPPPP
bad grounds. Look under the plastic cover on the l/s of the swing arm. There is a multi prong plug there that can get corroded and or have the wires damaged. If you've had the rear fender off, then you know where the cover and plug are.
Definitely sounds like a bad earth.
Check for corrosion in the lamps - you can get similar symptoms when the ground of a bulb isn't making electrical contact with the bulb-holder.