Stood near a bunch of torches in a large dark room, and could see torch-flames flickering intermitently in the air around them, apparently within a 10 or so block radius from the actual torch (though not confirmed). The flames appear in random sequences but they do seem to be linked somehow with the torch-flame animation, with the flickering often relating to nearby torchs' current frames. Sometimes the flames appeared in groups and other times they were scarce, with 5-10 seconds in between the flicker. As far as I am aware, the flickers occured on the same Y coordinate as the torch.
The flames flicker for only a fraction of a second and are hard to see if in the light, but in a large dark chamber they show up easier. It took me 10 minutes to get a screenshot, which only shows one flicker, but at times there were up to 4-5 per second.
Playing Creative mode, untested in Survival as of yet. In the screenshot, the flicker is visible just above the crosshair.