Nether portal cords bug

I was in the overworld about the cords of 0 70 3100 and I got the illager effect from the banner illager. Then I went to the nether then my cords were 0 70 3100! Then I went back in to see if it would fix it. But it didn't. My cords were 0 70 25000! I just made a new account because I forgot my last one/I got a new email. It would be cool if you figure out how it happened. Can you tall me if you do? I was woundering because I'm learning to code.