Seed generator does not work

It says I am in V1.5.1
When I try to put in a seed in the generator then load the world then leave and look at the seed is say something different this happens on different accounts on the Nintendo Switch there are two accounts and on both it changes the seed.
Example:-7866897547630675894 To 1830060826 and 7866897547630675894 to -1830060826

Rory Gatens Sent Me here when i posted this on the Minecraft Console Edition.