So it is a cheapo 12v PSU from Amazon, so I’m not holding out much hope that it’s especially good. Just decent enough and for cheap.
So what it is is a temporary flickering. Like the PWM rate drops low enough I can see it. Rather than the normal which is I can’t see any PWM at all, just a smooth dimmer/brighter.
And you mean put a electrolytic cap cross the input +/- wires? I thought it’d just be inline on the V+.