To reproduce:
Simply throw an invisibility potion at an enderman. Its head is still fully visible.
See attached screenshots.
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As of 1.6 (possibly 1.5), this issue has changed. Spiders and enderman are both affected by invisibility, but still wrongly.
Spider eyes are solid instead of partially transparent
Enderman head is still visible
Attached new screenshots.
From a new test in 1.9, the enderman head is no longer visible.
The eyes of each still appear solid rather than transparent. If that is unintended, it is a separate bug.
New test in 1.11.
Spider eyes are still solid, Endermen are entirely visible. Can this ticket be reopened?
Confirmed in Android HTC 10 using Android 6.0.1.