film on top

Hi all,About a week ago I bottled about three gallons of straight cider (just yeast and juice) in a dozen wine sized bottles and the remainder in a half gallon jug. It was in the 3 gallon jug for two days short of a year, very dry, and by all reports, quite tasty.
I've noticed looking back in on the remaining bottles that some of them have what appears to be a skin or film on the top, some covering the liquid, some barely there. I tested one, and it smells and tastes fine, so I'm a bit puzzled.
Whatever it is, it wants to stay on the top of the liquid, doesn't dissolve into the cider, just sort of stays clumped to itself.
Some kind of fallout from the Star San? I'll try to get a picture up, but thought I'd see if this sounded familiar to any of you.
Thanks,
HC

Here are a couple of pictures of what I was describing above. Out of 12 bottles maybe 3 have exhibited any form of this, the rest are clear. No bad smell, tastes fine, no hissing when opening the bottle.

https://cdn.homebrewtalk.com/gallery/showphoto.php?photo=40209&cat=recent&limit=recent

https://cdn.homebrewtalk.com/gallery/showphoto.php?photo=40208&limit=recent

As always, your observations are greatly appreciated!
HC

Hard to tell from the pics, but this looks more like bubbles from a referment than a film. Sometimes there is a little bit of activity when a cider is racked or bottled. Was there a small bit of carb on the one you tasted?

Hi Kevin,
No carb whatsoever, and the film seems to hang together, almost like a grease spot on water rather than bubbles. Give it a shake and it breaks into flakes that float back to the surface. The smell is like a very dry white wine, with an under taste that I can't quite put my finger on, not quite vinegary. And yet it doesn't taste spoiled, just not quite right.
Can the taste change after bottling?
Thanks,
HC