After Migration Redirect 404 not working

Hi, i changed my permalink and i did it with migration.

https://www.ads-software.com/support/topic/i-want-change-permalink-and-use-301-with-regex/

But after, when i open a sample url in browser for example: site.com/asasdjas3245ljsad/ this page should go 404 page, but just homepage opening, if i delete redirection plugin then site.com/asasdjas3245ljsad/ this page going 404 page.

Do you know why?