The bug
The text on signs has a black background when looking at it from certain angles.
Linked issues
is duplicated by 5
MC-161411
Sign texts get blacked out when using Programmer Art
Resolved
MC-161532
Sign Covered Up In Black Sometimes
Resolved
MC-161597
Graphical bug with text on signs
Resolved
MC-161629
Sign text is replaced by thick lines
Resolved
MC-161650
Text on signs are black blobs when rendered from a certain angle
Resolved
Found something very interesting: Maps in item frames being rendered seems to affect this glitch (along with a few other glitches):
[media]