Yes, that is currently a big problem. The companies have finally started to care about PWM, but they don't care much about remaining flicker. It is as if they think that no one would be affected by smaller flicker. There is little effort to produce truly constant light output. They label their products as "flicker-free" when there is measurable ripple that still causes eye strain and headaches. The current flicker standards don't help, as their thresholds of both flicker frequency and flicker percentages are set way too low. Progress in this area is unbelievably slow.
For example, I see it on the current TV I'm using as a monitor: 22 kHz, < 1%* ripple, usable. But when I switch inputs, the backlight readjusts itself to 22 kHz, 3-5%* ripple. That's too much already - symptoms within seconds. The current flicker standards consider these values "safe" by a large margin. The research data the standards are based on must be completely wrong. It seems they didn't ask persons that are sensitive enough.
*(Flicker percentages only roughly measured, as "(a - b) / a", a formula which produces higher values than those found in the standards papers.)
Another problem is that some LED backlights (or even LED room lighting, while we're at it) may take several minutes to "warm up", during which they flicker much more than later on. If you come across a flicker review it is never clear if they took this into account. The problem here is that symptoms can be caused instantly and persist for hours. A safe LED (back)light needs to have instant stable light output.
If anyone wants to measure with equipment, have a look at our oscilloscope thread: https://ledstrain.org/d/312-homemade-oscilloscope-to-detect-pwm-diy-guide
