Tony,
As you know... this has been a mess for me... but 550 ohms sounds really low. I'm using a 1K resistor pack per the parts list. I mean, low resistance isn't an issue but I'm wondering what is your resistor pack value? Can you check continuity between each side of the resistor pack and each leg of the LED's? This is what I did to make sure I had all of the legs on that side of the resistor pack soldered. I mean I know you're measuring from the common side, but it's best to make sure you have complete continuity along the line. Perhaps that 550 ohms is going back from ground through the LED and you're actually measuring the resistance across the LED

That's a couple things... The lighting up seems to point to a bad ground I would think. I mean, at least that is what it is in another circuit I am working on where the voltmeter triggers a ground situation and causes a switch to flip.