Nether portals do not work how intended. They do no follow the divide by 8 rule. Instead they spawn me in the nether at the same coordinates as the over world. Also sometimes I spawn in nether world or over-world without a nether portal at spawn. Sometimes if I don't move when there is no nether portal at spawn after going through a nether portal it'll rebuild terrain and spawn me at an active nether portal 100,000 blocks away in the overworld. Its frustrating  because sometimes the intended portals I have set up between the nether and overworld sometimes work fine and teleport to each other no problem. But 6/10 times the same portals just mentioned  encounter the bug described above.  Please look into it thank you. Also every time I go mining in the nether and then try to go back to the over world through the portal I came in, it spawns me near the original minecraft world spawn. Instead of the intended portal and it becomes it new portal that is unlinked to the intended portals.