Pi Zero W - blinkt performing oddly

Finished banging head on desk. Now need assistance from more experienced users please!

I have a Pi Zero W and 4 blinkts (purchased through another retailer). I have tried to run some simple python 3 test code to test my blinkts but get very strange results. For instance trying to set LED 0 (only) can result in all LEDs lighting (in various colours)! All of the blinkts are behaving in this way. I briefly considered that maybe my pins were poorly soldered but had discarded that as an idea given that the blinkt seems to light up ok (i.e. obviously getting data in, obviously getting power in). Writing this now though I also wonder whether maybe the data / clock pins may be poorly soldered (e.g. soldered so as connected)?

So now I am left wondering if I have done something stupid with my coding. I have included below the code that produced a rainbow array of colours:

from blinkt import set_pixel, clear, show, set_brightness

clear ()
show ()
set_pixel (0, 0, 0, 255, brightness=0.7)
show ()

Should also add that I have installed all the apt and pip packages listed on this forum post: Prerequisites for Blinkt boards on Raspberry Pi 3? - #9 by gadgetoid

Thoughts and suggestions encouraged and welcomed!

Should also add that LED 0 always displays as dimly as it appears in the attached picture

It’s hard to tell from your photo, but you should use the wiring detailed here: https://pinout.xyz/pinout/blinkt

Physical pin 2 for power and pin 6 for ground.

Also you should continuously drive the Blintk! since it could interpret noise on the jumper jerky as a signal and do all sorts of crazy things:

from blinkt import set_pixel, clear, show, set_brightness

while True:
    set_pixel (0, 0, 0, 255, brightness=0.7)
    show ()

This makes sure it’s updated with what you want to show continuously.

Thanks gadgetoid. That didn’t fix my problem, merely changed it (now only getting LEDs 1 through 3 light up instead). However, I did note flutter in the output when I was trying this so now wondering whether my jumpers might be the issue. Will try mounting direct and see if that gives me a better result.

Can confirm pins 2 and 6 for 5v and ground respectively

Any luck with mounting direct?