In this snapshot, if you get a spawner and/or find a spawner, it will spawn them inside of the walls, rather than inside or around them. in Any other version, That doesn't happen, Except for 14w26c, as that also has the bug.
MC-60685
Spawners spawn Entities inside of blocks
Resolved
Duplicate
0
Duplicate of MC-57831 – If you searched the tracker before creating this report, and were unable to find the indicated ticket, please comment with the keywords you searched for so that the original report can be improved.