So I have a world in bedrock edition 1.13.0. I created a portal in the overworld and went to the nether. Then I returned through the same portal and it spawned me in a cave nearby. So I destroyed the new portal, went back to my house, and tried again. Then it stuck me in a different cave nearby. And it does this every single time

Yes I completely destroy those portals Yes it's a different location each time I've tried moving my real portal And my portal is directly lined up with the nether coords (accounting for the 1/8 distance in the nether).