How often do refresh tokens expire?

Hello,

I see my refresh tokens fail regularly with the following error.

{"error":"invalid_grant","error_description":"The provided authorization grant is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client."}

I did not revoke or change the redirection URI so by elimination, I am assuming it expired or was issued to another client.

Is there a time limit on the refresh token? Under what circumstances would it be issued to another client?