I've brewed about 10 or 15 5-gal patches so far, so I'm pretty new at all this. On two of my more recent batches, I've had some sort of scum develop on the surface of the beer in the secondary fermenter (glass carboy). Even though I don't allow this scum to get transferred during bottling, I end up with a similar thing in the tops of my bottles. It looks like yeast, but it stays floating at the top.
I don't know if this is a coincidence or not, but I should mention that on these two batches, a fair amount of liquid from the airlock got sucked in (I use sanitizing solution).
The beer tastes fine, but the floaties have to be fished out before I can drink it...kinda gross.