I have an odd one here for sure.  

I am an exchange administrator for a organization and we believe that since getting iPhone 6's two of my execs have had an issue where their iphone AND their ipad have issues.  It is reported that a reply to all will cc themselves on every email and we found that when looking at the mail account settings the username actually changes from username@primarysmtp.com to username@internaldomain.com.   

We see this on both of the devices (iphone and ipad) and we feel that it began when they two execs got their iPhone 6's.  

I will also add that we do not have any way for these devices to communicate with our internal network other than just ActiveSync.  There is no internal wifi network or anything like that.   We have updated the device to the latest version of iOS and we just migrated their mailboxes to Exchange 2013.  I will add that this happened on 2010 as well and the migration just happened to be occurring during the time that we were trying to resolve it.  It has been going on for quite a while, but is starting to make a scene internally.   

We have since found that some of our regular users have this issue as well, but no one in our IT staff has seen this.  I am an Android user, but the rest of my staff are iOS users.  

Anyone seen this before?  Any ideas?  How could this just flip the account settings like this?

Sounds very similar to this:

https://support.microsoft.com/en-us/kb/3012580

Here are some more issues with EAS and devices as well in case this isn't it.

https://support.microsoft.com/en-us/kb/2563324?wa=wsignin1.0

very interesting article.  So here is a screenshot of my user.  We use GFI faxmaker and that is pointing to username@internaldomain.com the SIP and SMTP are pointing to username@primarysmtp.com.  I tied to delete the FAXMAKER address and recreate it as faxmaker (lowercase) but it flips to upper on its own.  According to your article, the uppercase designates a primary SMTP which could certainly be our issue.  Not sure yet, but this could be on to something. 

Faxmaker is a GFI product that we use for faxing.  Anyone else seen this?



we found that the faxmaker primary smtp address was the cause of this.  Very odd but it has fixed it for everyone so far.  We changed them from username@internaldomain.com to username@primarysmtp.com and success!

Thanks for the link.  It helped a TON!

• Marked as answer by bbjewrican 13 hours 26 minutes ago