Your soldering is indicative of an 'iron not hot enough and left on too long' so I would not be so quick to blame a bad batch of LEDs that were damaged by you.
i had the iron on for plenty of time though. it may have been poor soldering, but I tugged lightly on each one to make sure it was secure.
The first photograph looks like the data is connected to pin 7 not 6 like the software
And you are both wrong because the angle is apparent and you can see the space for the header end which is an empty pin 7.