Mobs are spawning in the space between a block and an upside down slab. To recreate, simply build an area that is completely enclosed where there is a block and then an upside down slab, similar to that of using slabs for floors.
MC-156341
Mobs spawning in half block spaces under slabs
Resolved
Duplicate
0
Zack Jenkins
(Unassigned)
Unconfirmed
(Unassigned)
Minecraft 1.14.3
Retrieved
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We're tracking this issue in MC-150333, so this ticket is being resolved and linked as a duplicate.
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