I was playing minecraft on normal and exploring the world at night when I noticed that there was way more mobs than it used to have, also I made a house in a plain creative world and in less then a minute it was infested with hostile mobs, As I said before I was playing in normal mode, I also tested in easy and the same thing happened.
My survival word was made in 1.14 and passed to 1.15 and now 1.16, it only happens when I generate new terrain, but in the flat world anywhere I build something closed the mobs spawn too much
I havent noticed anything weird with neutral or pacific mobs