This doesn’t make sense.
If 5.25mA is the resistor/LED current, 5.25mA * 220 Ω = 1.155V and you said .54V 
How and where are you measuring 5.25mA ?
Is the level on the i/o pin a constant HIGH or is it pulsing ?
Show us a good image of your ‘actual’ wiring.
Show us a good image of you measuring the LED current flow.