The bug
When a block shares a block space with an item frame, the comparator cannot detect the rotation of the item in the frame.
To reproduce
Place an item frame with an item inside it and a comparator behind the block it's on.
Place one of the affected blocks, for example a torch, in the same block as the item frame.
Turn the item
→ The comparator turns off
Linked issues
is duplicated by 15
MC-45949
Signs disrupt item frame comparator output
Resolved
MC-48310
Itemframe redstone signal not updating/outputting when torch placed on same block as the frame
Resolved
MC-48652
Comparator doesn't give an output from a item frame if a button exist in the same block.
Resolved
MC-51547
Vines, Torches Etc. Break Comparator / Item Frames Redstone Signal
Resolved
MC-67359
Item frame comparator not outputting if frame on same block with torch
Resolved
10 more links
relates to 1
Attachments
Comments 36
This posts issue seems to be solved as of Snapshot 14w25b, but the issue with it not outputting signal of an item's angle in the item frame with a block such as a button, torch, vine, or ladder is still an issue as of 14w25b. The post said as duplicates explain this in more detail.
26 more comments
Is this still a concern in the current Minecraft version 14w20b / Launcher version 1.3.11 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.