Greetings.
The rDNS messages would affect your outgoing emails, not the incoming ones. As that is the case you would not need to be too concerned about this if your concern is incoming emails. If you wish to look into it further, then our analysts have created an article that you may reference
here.
Additionally, DNS changes take time to propagate. Propagation is a period of time ISP (Internet service provider) nodes across the world take to update their caches with the new DNS information of your domain. Due to DNS caches of different levels, after a DNS change, some of your visitors might still be directed to your old server for some time, whereas others can see the website from the new server shortly after the change.
If you find that you require assistance with specific configuration settings or you find that there is information that you prefer not to share in the public forum, then we highly recommend opening a support ticket using the resource that was provided earlier. We will link it
here for your convenience as well.