After updating previously existing routes in the _routes.json file and changing languages, it will still redirect to the old route and will give a 404. I was able to recreate with the example project, I downloaded it and ran it, then changed the french redirect from "blog" to "blo" and re-ran the project, I was still redirected to "blog" when switching languages. If there is something I have to do after updating the file let me know.
After updating previously existing routes in the _routes.json file and changing languages, it will still redirect to the old route and will give a 404. I was able to recreate with the example project, I downloaded it and ran it, then changed the french redirect from "blog" to "blo" and re-ran the project, I was still redirected to "blog" when switching languages. If there is something I have to do after updating the file let me know.