My 07 road king i noticed the other night the light on the speedometer would cut out for a split second then come back on while riding. Did it randomly and with no other symptoms. Today noticed its cutting out faster almost to the point it looks like its flashing. This include the 6th gear indicator.

 

Lose connection? Check connectors and move wires around and try to duplicate your issue. Otherwise, it's a Poltergeist.

 

If it's different bulbs in the same mount, it's the ground connection.