Ender Dragon will fly to world high if portal is blocked

isn t it normal?? 

seems like that shouldn't happen to me  

Steps to reproduce

1. Place an obsidian or other dragon immune block at (0, 255, 0) in the End

2. Summon the dragon

3. Wait for her to perch

Expected result
Dragon perches on the exit portal

Actual result
Dragon "perches" on that obsidian block

See also: https://www.youtube.com/watch?v=f2gKoNikiik

This ticket is actually a duplicate of MC-207174.

Dupe of MC-207174