Remote MX, vs. locally delivered email: still broken!

[jols]

Here's the situation:

1 - The hosted account uses their own email server, therefore the MX for the domain directs email to an off-server location.

2 - They use a FormMail driven contact form on their web site.

3 - They do not receive their FormMail sent email.

4 - The following option in their DNS record setting (in WHM) is NOT checked:
Always accept mail locally even if the primary mx does not point to this server.

5 - I remove their domain from the list at /etc/localdomains

6 - It works for them for a while, until the next major cPanel update.

7 - We receive another complaint that their FormMail sent email is not being delivered again.

8 - We check /etc/localdomains, and find that their domain has been re-inserted, thus causing the issue.

And, on and on and on.

Is there any resolution for this?

[FreedomBI]

I have a workaround.

First, I have a file, /etc/remotemaildomains, which contains a list of all domains that handle their mail elsewhere.

Then, in the exim configuration, I define:

domainlist remotemail_domains = lsearch;/etc/remotemaildomains

And set up a router:

remotemail_domains:
  driver = manualroute
  routelist = +remotemail_domains mailrelay.freedombi.com
  transport = remote_smtp

I assume your setup is a little different, so you'd have to adapt that to suit your needs.