When digging any kind of half slab (stone, quartz, stonebrick) using a diamond axe with an efficiency enchant it will mine it faster than it should.
Steps to Reproduce:
1. Get a diamond axe with any efficiency enchant.
2. Place down any kind of slab that isn't wood
3. Dig the slab with the axe.
Duplicate of MC-11027, please use the search function to see if your bug has already been submitted. Currently over 57% of tickets are being resolved as duplicate.