Rigger
The very first thing to check is the tail/brake light bulb.
The OEM bulbs have a very short life and although the good ones you can buy at a auto parts store are much better, those bulbs live in a hazardous area.
The vibration from a big single like the RE can cause the entire rear fender to vibrate up and down rapidly at certain engine speeds.
As for the turn signals, maybe you should count your blessings?
The OEM signals on my 2011 G5 work like they are supposed to.
That is, if I push the switch to the right, the right bulbs start winking. Likewise, the left position turns on the left side.
The problem is, in order to get the damn thing to stop winking I have to push the button straight in. If I push it in and to either side at the same time it just keeps on winking.
If I had to hold it in position to get it to keep winking, I could live with that. It would also guarantee the signal will stop winking when I stop pushing.
As it is now, I have to look at the green light in the speedometer to see if it is still on.
Like most riders, this means there are times I ride for a long distance after I've turned before I realize it has been winking for a mile or two.