Minecraft wiki entry for Development_versions, associated text: MC-160931 – 1.15 chunk rendering is slow and laggy.
MC-161844 – Resource pack version has not been increased, despite resource packs from 1.15 snapshots being incompatible with 1.14 resource packs.
MC-161900 – Advancement menu background is rendered in front of toasts.
MC-163369 – Summoning a leash knot using the command is broken.
MC-163553 – Dragon texture flickering issue.
MC-163560 – Berry bushes no longer slow down the player.
MC-163745 – Dramatic speed up after falling through a cobweb.
MC-163947 – When mobs sliding down honey blocks, the subtitles will show footsteps.
MC-163953 – /fill command does not create block entities for all bocks.
MC-163982 – Semi-transparent entities are rendered behind clouds, transparent blocks, breaking animations, etc.
MC-164076 – Transparent texture parts of invisible entities are rendered black when looking at them in spectator mode.
MC-164535 – /playsound uses wrong feedback message for multiple targets.
MC-165133 – Ignited TNT appears to offset one block to the west.
MC-165134 – Entities are rendered too dark when in the ground.
MC-165153 – Breaking animation no longer renders behind transparent blocks.
MC-165154 – Entities riding boats, minecarts or other entities are rendered too dark when their hitbox intersects solid blocks.
MC-165155 – Block hitboxes no longer render behind transparent blocks.
MC-165156 – Transparent block items no longer render behind transparent blocks.
MC-165173 – Bees immediately enter their nests/hives after leaving them.
MC-165225 – Dropped items do not render behind transparent blocks.
MC-165252 – Banners are rendered completely white when looking at them through transparent blocks.
MC-165276 – Items held by entities do not render through transparent blocks.
MC-165298 – Entities are rendered too dark when standing on soul sand or snow layers.
MC-165339 – Shulker boxes do not render behind transparent blocks.
MC-165358 – Entities are sometimes rendered too dark when changing heights.
MC-165422 – Some player heads will only render behind tinted glass if you look at a block.
MC-165497 – Programmer art shield pattern textures have not been updated to the new resource pack format.
MC-165527 – Item of advancement pop up is visible on text in the advancement menu.
MC-165531 – Conduit does not render.
MC-165573 – Filled item frames do not show the item when viewed through glass.