You can see moving blocks and colored text behind the visible area when applied with blindness effect.
MCPE-20569
Moving blocks and colored text are visible through blindness
Resolved
Fixed
2
(Unassigned)
94908
Confirmed
Android
1.0.6.0, 1.1.0.1, 1.0.6.52, 1.1.0.5, 1.0.7.0, ..., 1.0.8.1, 1.1.5.0, 1.2.0.25, 1.2.8.0, 1.2.10.2
1.11.1
Retrieved
Fixed possibly 1.2.13 and earlier.