No - there is nothing wrong with your false bottom, don't worry.
You will want to check to see if the silicone gasket (black) was fitted up properly to the false bottom and/or whether it slipped off when you put the false bottom into the tun. Spray a little sanitizer around the edges and it goes in easier.
If the particles you are seeing are really small, but larger than "dust" - it would
imply the grain bed didn't get set properly. Most brewers have seen clear
wort after just a few quarts of vorlaufing. But depending on your mill
settings - could be more or less than that.
One key point, is to drain the liquid down to have between 1/2" to 1" of
liquid above the grain bed. The bed will compress, as you start pulling
the liquid off. . . . and you should be able to see the liquid level,
once you hit the 1/2"-1" you can pour the the wort back over the top of
the grain bed until it flows clear.
If you have too much liquid in the Tun, the bed will never "compress" or set up properly. And it is this compression or "set" grain bed that provides the filtering.
It also could be that you just didn't have much / enough grain in your grist. A really thin layer of grain, will never set very well and will pass more grain through under the false bottom. That's simply because there's not enough thickness to create a a good filter.
The last factor would be related to mill settings. If the material was really powder like - it would imply your mill was set too fine. . . and your percent of flour was disproportional to the larger materials. In this case, if the bed is set it would normally clear up - but you should take a close look at your mill setting.
Hope that helps!