But what was weird was that if I touched the Multimeter probe to the first one (IE like it was soldered). It works. No more glitching. So I re soldered the wire, and the glitching comes back.
Now, If I touch the multimeter probe (not connected to anything), while the wire is soldered, the glitching goes away!. WTF?
This sounds like a signal quality problem. Your description mentions a level shifter and resistors, so if those resistors are well matched to the cables, in theory the signals should be good.
In practice, impedance mismatch causes funny ringing and other signal issues. Limiting the bandwidth slightly, like forming a low-pass filter with the 135 ohm resistor and capacitance of your multimeter, can slow the signals enough to lessen those issues.
The new OctoWS2811 adaptor board was made to help with exactly these sorts of issues. CAT6 cable is precisely controlled for 100 ohm impedance on each twisted pair, so it always matches closely to the 100 ohm resistors on the circuit board.
http://www.pjrc.com/store/octo28_adaptor.html
I know this sounds like a sales pitch, and truthfully it is. Get this $10 board.
In hindsight, I should have made this adaptor a year ago. In fact, earlier I designed another much bigger one with power distribution and fuses, which looked awesome, like professional-looking industrial control modules often look. But it was entirely the wrong idea. The last thing you want to do is have the LED ground current running through the same ground wire that is the signal's ground. But that's the way most people hook these projects up, because the 3 wires run together with the LED strip, so it seems intuitive to run them together when you wire things.
Using CAT6 cable, where each signal gets its own ground, and a wiring approach where the LED power grounds are separate and meet at the LEDs, not at the Teensy, gives you the best chance of reliable signals. Well, the best chance without resorting to much more expensive ways of doing things.
I really did make this $10, not because a $10 product is going to be huge for PJRC sales-wise, but because these big LED projects are so easy to build but so hard to make really reliable. There are dozens of threads on these forums, and hundreds of old emails I've answered, with all sorts of really difficult "basically works, but flickers when..." issues, which have almost all turned out to be signal quality problems.
My hope is this adaptor will save you and everyone else a lot of grief.