I was playing in singleplayer and after a while i left the game making sure to save. Once i reopen the game, my item frames were missing. Also, i went to a village, 1160 block away from my base and came back with no problems. I decided to link the village and my base with nether portal. So once i put a portal in the village and link it to the nether one, i went back to my base to see all my animals (Chickens and Cows) missing. Also, the green villager as also dissapear but not the other ones.

What I expected to happen was...:
I expected to have all my animals/entity were they were originaly

What actually happened was...:
All animal/entities vanish once i came back

Steps to Reproduce:
1. Spawn in entities/animals (For me it was item frames, cows, chicken and green villager)
2. Go a little over 1000 block away and put a portal (Make sure to write down the cords)
3. Go back to you base (entities may have already dissapear by now if not continue to step 4)

4. Make a nether portal to base and go in

5. Once in the nether, go to the cords of the first nether portal (make sure to devide the cords in the overworld by 8)

6. Put down an other portal and go in. You should now be where you put the first portal

7.Go back to your base using the portals. You should now have all your entities/animals dissapear