this is by design. actor ids (unique identifier for accounts) should not be reused due to undefined behavior for how other instances will deal with that.

if you want to have a more technical explanation, https://socialhub.activitypub.rocks/t/reuse-of-identity-channel-addresses-revocation-reissue-of-keys/2888 does a decent job at explaining some of the issues with this.

I recently read a complaint about the opposite. Someone deleted their Proton account and their handle was made available 1 year later. They were rightfully angry because the next user would potentially start receiving mail from things like the original user’s bank. The new user could perform password resets on accounts where the original user had not yet changed the email address on file.

it is the chance for mahmoudk1001 to show his value!

That's not a bug, it's a feature. ™️