Yes. It does happen again, if the cage is 3x3
I could fix it by adding a Scoreboard team with collison rule Never.
=> Mobs can glitch out of a box, if they are to "fast".
Screenshots of it
There are those 2 things
after Server restart it was normal again
EDIT:
I reuploaded the Map and it was there again..
Restart helped. Maybe a Bug with first time server loading the Map
Dropping: http://hastebin.com/elurumiwut.coffee
Picking it up: http://hastebin.com/dusizaguhe.coffee
Server IP: niklask2001.de:25564
There are no errors in the Console / ServerLog
On what? putting it onto the ground or picking it up?
Dupe of MC-142521