From R4L Help Wiki
Forwarding Problems with Google's GMail Account
- Emails that are forwarded to a Gmail based account are accepted by google's mail servers, but never show up in your Gmail account. In order to solve this problem, you will need to go under the Settings->Accounts. From there, you can add other email addresses under the "Send mail as:" section. Please add your R4L Alias(es) there, and then test the forwarding again. This should solve the forwarding issue.