thanks
the bug in my mind is the fact that the sprite snaps to the mouse briefly
rather than not reacting to the player.
I don't think i was holding shift. I placed them in an earlier snapshot. If i placed new ones then they worked again. It hasn't happened since. It was as if the item frames weren't really there, but they were visually there. I was getting a comparator output from them if that changes anything.
Is this related at all to the player spawning in blocks. This occurs both in creative and survival. I do not think that it is limited to certain biomes. Although I have seen it in both jungle biomes and extreme hills biomes.
Duplicate of MC-47520