Yup. Except they flicker at double the mains frequency because they use both the positive and negative half-cycle thanks to a FULL BRIDGE RECTIFIER.

And see my other comment: it's not unhealthy, just annoying. To be honest, I use trash-picked LED bulbs and repair them, and I don't normally care to replace a poor smoothing capacitor. In rooms I spend much of my time, I make sure most bulbs in the fixture are low-flicker (it's arbitrary but generally don't get below 75%) for comfort. I'm not peculiar about light quality like CRI and matching color temperature unless it's very obviously bad, although I do notice the circadian effects of cold white light. I do mark badly flickering bulbs though so I know not to put too many of them together unless it's somewhere non-consequential like a cellar. I also hold my phone camera to any neutral-white E27s I salvage to find and mark true flicker-free ones because I use them while filming.

That just means the driver is not flicker free, not the LED board itself, and there are flicker free drivers out there but they're just not available for the average consumer.

But visible flicker? On an LED that's just emitting light? I've never seen that before. Maybe it's a UK and Europe thing.