Every single mob disappear after I came through portal (Nether portal & End Portal). The first time it happened was when I came through the end portal and I spawn in my villager breeder and zombie curing area, end when I checked every single mob there, all of them disappeared. The second time it happens was when I came through the nether portal to my base, and I found out that every single mob in my base disappeared (horses, cows, sheep, bees, pig, chickens). I worried if every single villager in my villager trading hall will disappear also.