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
relates to
Attachments
Comments
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.
Still affects 1.8 pre-2
Unsurprisingly, affects 1.8 also.
Still affects 1.8.2-pre4
Affects 1.8.4. Gah.
Affects 1.8.6 - how am I ever going to get my secret torch passageway working at this rate :s
Affects 1.8.8 and 15w32c.
Affects 15w50a.
Affects 1.9-Pre 2 :/

Confirmed for 1.9

Still in 1.9.1-pre3

Still in 16w15b
Affects 1.9.3-pre1
Still affecting 1.9.4
Affects 16w32b. Some day my bugfix will come...

Confirmed for Minecraft 1.12

Affects 18w22c

Affects 1.13-pre1

Affects 1.13-pre2

Affects 1.13-pre3

Affects 1.13-pre4
Confirmed for 1.13.1-pre1.

1.14 first 2 snapshots: same

Tested with difficulty in 19w05a
Affects 19w08b

Also blocked by MC-154499 in 1.14.3-pre3

No longer blocked in 1.14.3-pre4
Affects 1.14.3, 1.14.4-pre1, and 1.14.4-pre2
Affects 1.14.4-pre3
Affects 1.14.4-pre4
Affects 1.14.4-pre5
Affects 1.14.4-pre6
Affects 1.14.4-pre7
Affects 1.14.4
Glad to see this is finally assigned after "some" waiting 😃
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.