I can’t get LEDs to work together in twin wired Port Charlotte lights. I can put in an incandescent light with an LED bulb and just the led works. I put both LEDs in and neither works. I put both incandescent lights in and they both work. Power shows present on voltage meter. Could it be the switch? I have a standard light switch from 50 years ago technology
Given the symptoms, I have to suspect that this fixture is wired with the bulbs in series, rather than with the bulbs in parallel.
So, two incandescents - operate happily if somewhat dim and yellow on half-voltage. Bulbs would last a long time and veer towards "bug light" yellow without the ugly yellow paintjob, so it's not unreasonable for a "porch light" fixture.
One LED one incandescent - adequate voltage for the LED, so little current you don't even notice the glow on the incandescent.
Two LEDs - half voltage, ain't nobody happy.
Diagnostic - one bulb, one empty socket - what happens?