Mobs don't drop XP points nor items after they got killed in my world

1. Mobs especially hostile mobs don't drop Xp points and items after they got killed, even though I used Looting I Diamond Sword.
2. I can't make farms because of this bug.
3. Although mining ores drops Xp, it's still hard to mine all ores.
4. It was happened July 17, 2021