To fix old 301 redirect use this link https://chlp.github.io/301-redirect/redirect301CacheCleanPost.html?url.

For exmpale. You change redirect on page https://prover.io - follow link https://chlp.github.io/301-redirect/redirect301CacheCleanPost.html?https://prover.io and it send post request to https://prover.io and browser recache (even 301) redirect.