Starting from the top, I see your first board has what might be a common problem.
The tiny pins inside all the connectors can bend over if you plug the connector in a little sideways, after that, the more you push, the more bent the pin. Use a magnifying glass and try to look at all the pins.
If you find a bent one and it is not too bad, you can use a magnifier and modeling knife to start to straighten it and an EXTREMELY thin needle nose pliers or hemostat to clamp the bends out.
Other than that, don't mount with metal anything (screws, standoffs) or mount touching a metal or carbon surface.
Don't feed them more than 6 volts (preferably 5). Original spec was higher voltage than that.