in validation tokens method i have a problem

[ehsan-shafieinejad]

when I use validation tokens such as $result = $messaging->validateRegistrationTokens($tokens); I Expecting that "valid" field may be "contains all tokens that are valid and registered to the current Firebase project base of documentation."
but I have many tokens that report valid with this method but when send failed because get error "Requested entity was not found." from fcm. this is because my user delete cache and get new token, then old token break. why this report valid? and how can filter all token database as valid periodically? I want have valid tokens in my db.
please help me.