What could cause a ring at the top of my cider?

I've posted the same question in the beer forum.

Two weeks ago I bottled 6 gallons of Brett beer, and followed that with 3 gallons of cider brewed with the same Brett yeast.

I siphoned the beer into the bottling bucket and bottled. Then siphoned the cider into the same bucket without cleaning (probably about 4 to 6 ozs of beer still in there), and then bottled the cider. I had dry hopped the beer (with pellets) and a few hop pieces were in the bottling bucket; they usually end up in the final bottle.

The Brett beer ended at 1.002.

The cider was apple juice (obviously) + 0.5 lbs Honey malt (mashed) + sugar to get to 1.060.

The Brett beer is great. Looks great in the bottle, pours great, and the one I had last night tasted great.

The cider has a film/ring on the top. I've brewed about 190 batches of beer and 20 batches of cider and never had anything like it. Every bottle of the cider has this on the top of the liquid.

I'm drinking one of the ciders right now (last bottle filled; has 3 flakes of the hops in it). Tastes fine. Not sure about the honey malt, seems to make it a little too sweet tasting for me although it finished at 0.996.

Any insight as to what could have caused this ring would be welcome.

Might be something settling out from the beer. Is it a thick layer? Is it oily/crusty or something else? Can you get a picture of it?

Agreed that it sounds like something settling out from your beer. Could be a light film yeast, but that usually takes some time to develop. How long has your cider been sitting around, and under what conditions? Film yeast looks, well, filmy on the top and doesn't have much of a taste, in my experience, in the early stages. The cure is 100ppm k-meta as soon as your confident that it's film yeast. Much easier to tell with a photo.