Faulty 2-colour led?

One (Led 12) of the 2-colour leds (LED 3 RY from Reichelt) only work on one of the colours, the yellow one. Swaped colours with software and stays the same, checked solder joints (led, resistor, ic) but seems ok.
Could be the LED just faulty? Is any way to check it?

LED check :
Step one, apply power.
Step two, check for light.

2 Colour LED check:
Step one, apply power.
Step two, check for light.
Step three reverse LED, or power, start over.

(note, power should be applied trough a appropriate resistor.)

Thanks. Anyway received leds from Mouser and changed them.