1998 Acura Integra One blind Brake Light Problem

98 Acura Integra 2Dr LS Automatic.

When the headlights are off the rear brake lights work. Turn them on and the rear passenger brake light turns off and doesn't work. All other lights unaffected and work fine. Upon closer inspection when the headlights are off the same light does work but seems slightly dimmer than the left.

I've done the "regular" things such as checking fuses and replacing bulbs and checking that the ground wire is still connected. To no solution. I was thinking about buying a replacement wiring harness for the lights but not sure if this is the fix or if its something else entirely.

Any suggestions on what I need to be looking at/for to fix this? Thanks for your help!