After updating one of my worlds from from version 1.14.2 to 1.14.3, I noticed a lack of hostile mobs once the sun set. Also, there is a lack of mobs spawning while i searched through a cave. The only time I encountered a hostile mob was when I found a dungeon. I made sure that I was playing the world in normal mode, I cycled through all the modes for a while.
Duplicate of MC-155289