Minecraft wiki entry for Development_versions, associated text: MC-151225 – Upgrading worlds from 1.14 causes villagers to lose their brain memories
MC-151753 – More than one raid can happen in a village
MC-151771 – Villagers do not try to run away from zombie villagers
MC-151772 – Mob cap in the hundreds to over 1000 per player.
MC-151802 – Spawning causes massive TPS CPU load on a flat world.
MC-151995 – Patrol leaders spawn without banner
MC-152044 – Baby trader llamas disappear immediately