Weird Bulb Behavior

Oh and I forgot to mention this. I have an M&H (from Classic) restoration under dash wiring harness in this car. It has provisions for three flashers.... yeah THREE. Locations for these are one is on the left side of the steering column. One is on the right of the steering column just above the ignition switch, and one is mounted on the ash tray housing. WTF? I figured there would be two.... one for the flashers, one for the turn signals. And yes, in my troubleshooting I experimented with populating all of them, just one, and just two. But yeah... weird.
The third one you have is for key light above the ignition. One wire is yellow if not mistaken by memory? If you have a flasher plugged in there take it out. That plug is for accessory light package . Key light, Map light, Uses the door switch circuit for the dome light. Which is always powered and grounds to aluminate.