When looking at a block that has an item frame (full or empty) on it, if the bottom of your view goes above a certain point (five 'pixels' from the top of the block), then the item frame will vanish. This is a visual glitch, not a physical one: the item frame is obviously still there, and you will see it when you move the view again.
I noticed this glitch while watching xisumavoid's video here, at 2:00-2:02. You can watch the video to see the glitch actually happening. In the three screenshots I attached, I tested two adjacent netherrack blocks with filled item frames (like in the video), two adjacent dirt blocks with empty item frames (to see if the netherrack was the problem, or the fact that the frames had items in them), and a single stone block with an empty item frame (to see if the glitch occurs with a single item frame not next to any others). I can assure you that there are item frames on all of these blocks. I also tested this in all four directions (north, south, east, and west), and can confirm that it's not a directional issue. And it happens both in creative and survival mode.
I know this isn't an important issue, but I figure that if it is caused by a flaw in the rendering engine, then it could lead to much more significant issues down the road.