Password Change Causes Emails to be Erased on Iphone & IPad but not on PC Mail (Apple) App or Web

Hi.  Due to the data breach, I was forced to change my email password.  I logged in via web and changed the password (which i had also done with my wife’s xfinity account).  Then for both accounts i changed the password on mine and my wife’s iPhone, iPad, and MacBook in both incoming and outgoing settings.  That was the only change i made; an identical change to each account.  This allowed both of us to see our inbox messages and sent messages; they populated on each of our devices.  I first sent a test message from my wife’s iPhone xfinity account using the third party Mail (apple) app after having changed her incoming and outgoing passwords.  I saw the email enter my inbox (using my new incoming and outgoing passwords) then watched the email immediately disappear from the inbox.  It is not in spam.  It is not in trash. It’s just gone, without me deleting it.  Same thing occurred in her “sent” email box.  Yet, when i log into xfinity on web, the email is in my inbox.  When i log into her xfinity account on web it is in her “sent” box.  And, likewise, when I open my third party Mail (apple) app on my mac, i see the message in my inbox, and same with her account in the sent box. I did this test multiple times from each account to the other account, and it occurred multiple times. I then sent an email from each account (both accounts with updated passwords) to different, non-xfinity email accounts, and i can see them using the third party Mail app for those non xfinity accounts!  I checked the settings for the xfinity Mail app (apple) and they appear correct and consistent from Mac to IPhone.  I deleted my xfinity account from my iPhone and then added it using my new password and my user, and it populated, but those messages still do not appear in the inbox (those being the emails from my wife which I received while i had the new password, and likewise from me to her).  I also powered down the devices and then turned them back on.  To no avail.  This all occurred from a simple password change!