Ducky Shine Single Key Issue - Works only when lit.

[toy4x4]

The J key only works when lit. It does not work with all backlight levels, only the dimmest and 2 up from there?

All lights off:   does not work
ASDW Lights On: J works
All Lights On - lowest Dim: J Works
All Lights On - Next Level Dim: does not work
All Lights On - Next Level Dim: J Works but inconsistent
All Lights On - Next Level Dim: does not work
All Lights On - Next Level Dim: does not work

So I am wondering if it is going to be resolved by replacing the switch for that key or do I have some sort of other problem in the keyboard?

[KHAANNN]

That doesn't sound like a switch issue, might be a led issue - or a problem with the keyboard

Or just a soldering/contact issue etc, as the J doesn't work when all lights are off

[falkentyne]

Which ducky shine is this?
1, 2, 3 or 4? Mini YOTS? YOTH? There are TONS of ducky shines...

But sounds like a voltage problem.  I'd RMA it.  This probably isn't user fixable unless you are good with a multimeter and a soldering iron, as it could easily be a solder point, corrosion, a resistor or capacitor at fault here.
A bad switch can't cause this.  Switches either make a contact (completing a circuit) or they don't....
However if you do have spare switches ready and a soldering iron, and you are experienced, there's nothing to lose by trying...

[toy4x4]

It's a 9008S-B.   Been so long since I bought I I don't remember much else about.

I'll take it apart and check for cold solder joints and trace the voltages.