Mobs teleport back to a nether portal several seconds after they came out of it

I WILL NOT BE UPDATING THIS IN THE FUTURE BECAUSE I AM GETTING RID OF MY SWITCH

Steps to Reproduce:
step 1 - create world with seed 8609191581245315983
step 2 - create nether portal at -1 67 -15 in overworld
step 3 - create nether portal at -3246 95 -2910 in overworld
step 4 - take horse into nether through one portal and out the other
step 5 - wait for horse to teleport back to portal
step 6 - if nothing happens try repeating step 4 or try leave and rejoin the world

Observed Results:
after taking mobs through a nether portal they sometimes teleport back to the portal. after following them through the portal and loading their chunks, they sometimes teleport back to where they originally were.

Expected Results:
for them to not teleport.

Notes:
this sometimes triggered when i log back into my world, dismount or have the pet dismount me, or sometimes would just happen when i'm nearby not even interacting with them.
i also recreated this on my android phone.