** Update - Fixed**
After checking the voltages at the tail light socket and verifying that they were the correct values at the correct time (e.g when I turned on the lights and/or pressed the brake pedal), I then swapped in the other tail light bezel...everything worked as it should. This...
The drivers side tail/stop light is acting strangely. (the passenger side works fine). All references below are regarding the drivers side tail/stop light.
With the lights off, stepping on the brake pedal results in the stop/brake light illuminating. (as one would expect)
Now, turn on the...