Why do I not receive iCloud e-mails when there is a specific group of "To:" addresses in the body of an e-mail

Question

I noticed this when I started my iCloud e-mail account a few months ago. I am not receiving iCloud e-mails when there is a specific group of "To:" addresses in the body of an e-mail. I can receive the e-mail on my outlook & local cable providor e-mail accounts with all of the addresses listed. If I strip out the "To:" addresses and send it from my local cable providor e-mail account to my iCloud e-mail account than I will receive the e-mail in my iCloud account (minus all of the "To:" addresses that are in the body of the e-mail. This has caused me to miss a lot of e-mails.
Following is one of the e-mail that I can send from my cable providor account and not receive it in iCloud. If I strip out all of the "To:" addresses I will receive it in iCloud. I have a case open with Apple but it is not going anywhere. This occurs from multiple sending internet service providors (ISP's) so I think it's an Apple iCloud e-mail processing issue.

Answer 1

I've been having a very similar problem to what ziemsen describes, for about a week now. The Mail app has stopped delivering new messages to the Inbox, even though I can view the newly incoming messages on the server via Webmail. I am able to send email through Mail with this email account, and as for the other email accounts that I have on Mail (which are also hosted by the same server), I am able to both receive and send email with no problem.
None of the mail settings have been changed, so how this happened all of a sudden is very puzzling. I have checked Account Info on the problem account - Mail recognizes that there are messages that are on the server yet to be downloaded, but it won't download them.
I've checked what other users have suggested here in the Discussions Forum, and tried: 1) deleting the problem Mail account from Mail and re-adding it; 2) creating a new machine User account and setting up Mail with that User; 3) setting up Mail on another machine; 4) archiving and re-installing OS, and even 5) wiping the HD entirely and reinstalling the OS. None of these have worked.
Ernie, your suggestion of deleting the MessageUidsAlreadyDownloaded file sounded like the solution to the problem, so I just tried it - but to no avail. Mail delivers messages that are on the server to my Inbox up until the same point that it always stops at, and there are almost 1000 new messages since then.
I am pretty lost at this point - I have no idea what else I can possibly do to resolve this problem. The strange thing is, when I tested my email accounts on Microsoft Entourage and Mozilla Thunderbird, they don't have this problem - both deliver all of my incoming mail. I may have no choice but to switch to one or the other at this point, but I'm attached to Mail and would really like to continue using it if I can. Any advice would be much much appreciated.
very best,
biteringo