Minecraft wiki entry for Development_versions, associated text: MC-34661 – Thorns enchantment causes double armor decay.
MC-65953 – Tags IsBaby and IsVillager cannot be changed from true to false with /entitydata.
MC-80032 – Horses can suffocate when going through nether portals
MC-121098 – Entering a tall portal that takes you to a short portal from the top causes you to take suffocation damage
MC-131587 – Deep frozen ocean biome does not generate with ice on the surface.
MC-172221 – Hoglins, zoglins, ravagers, iron golems, and polar bears do not walk down a block if they are partially walking on air.
MC-179369 – Wandering traders are always invisible in the nether and the end.
MC-182868 – Rail updates are 4–5x times laggier since 1.14 if the rail is on top of a non-full cube.
MC-185925 – Casting issue: blob generation uses 32-bit floats, leading to precision loss and potential crashes.