I've completed the additional testing I mentioned above and basically confirmed my suspicions. Sadly, this is essentially the same issue I posted last year - but the post was deleted for being too technical.
I guess I will give it a shot again this year and strip it to the bare bones...
-->THE DATA LINE IS RINGING LIKE A BELL<--
To scratch the technical surface with basic analogies... the data is sent as square wave pulses on the data line. The PIC generates these pulses by switching on/off. But the current in the data line can't start and stop instantly, it take a fraction of a microsecond or two. When the PIC shuts off, the electric current is basically running into a brick wall and it bounces back and forth a bit. When the PIC turns on, a relatively huge amount of current rushes into the 'empty' data line. Both of these events leave the leading edge of the square wave data fairly frazzled. When the node can't read the square wave, it misinterprets the data.
Since the V2 SSC's move more current, they are actually more susceptible to ringing than the V1's. I'm seeing a huge amount of ringing with the V2 data line only 24 inches long. (got some great scope traces of it!)
So what to do about it?
The easiest thing to do is keep the data line as short as possible. I'd recommend 12 inches or less to stay on the 'more reliable' side.
The second possibility is to use 'null nodes'...but then you're wasting fairly expensive and pretty/blinky hardware.
A third option would be to put a resistor in the data line. I'd have to do a bit more testing here, too. But I suspect a 47 ohm resistor down by the first node would help 'impedance match' the node/line with the SSC. The downside is this also drops the 'signal' by a bit...but there may be some compromise between damping the ringing and lowering the signal level.
The fourth option - also may require a bit more testing - but just to see what would happen, I made a data line from 15 feet of 75ohm coax cable. The SSC V2 is driving the string 15 feet away without missing a color. The coax damped the ringing and actually boosted the signal a bit.
So to sum everything up, as far as I can tell, there is no SSC V2 bug. The V2 moves more current on the data line and is generating more square wave ringing. This is simply the result of sending high speed digital data down a plain wire. I would keep the wire to 12" or less to minimize the ringing. There may be other fixes available to get the length up to 15+ feet if needed, though.
Anyway, just my .02 - hope I have stayed on the non-technical side of a technical issue.