Server Seed mixed in with seed 0

THE SITE WILL NOT LET ME PUT 1.16.3, THIS IS NOT 1.16.4

I was using a seed map to get to a jungle biome and i went thru the nether portal on the nether roof to try and make a link and it kicks me to the menu and gives me a 'internal server error' , i come back and try and go to the jungle biome and its not there. my seed (-1484025669187821064) was some how "mixed" with seed 0, just the number 0. Some chunks of the world that I have rendered are from my original seed and the rest is seed '0'. Kinda weird