On Kubuntu 14.10 using KDE and KMail 4.14.2

I have some really old email that I once upon a time imported from Outlook somehow. We are talking pre-2005 email.

During a move of webhost I discovered that these email can not be "seen" in KMail any longer unless I go to menu View and choose View
Source!

On the server (this is IMAP) they look perfectly fine. Being created in Outlook once upon a time these are html mail, not that it should
make any difference.

if I from Roundcube, the webmail client, forward one of these email to myself it comes out readable in KMail. Somewhat mangled,
but fully readable. Whether I send it as html or plain text makes no difference.

Anyone have any idea how I might get them to show in KMail as mail, not "source" and not only via webmail client to server??

in a, to me at least, strange chain of events this problem was "solved".

here is what happened: "thanks" to my changing the location of my account from an ip-number to the format "mail.mydomain.com" KMail and
Akonadi (or however it works) decided that it was now a completely new resource.

It dumped all mail to infinity and redownloaded them fresh from the server and suddenly all mail are perfectly readable...

I still have old copies in Local Folders (had them on a pop-resource earlier and I am these days VERY careful about deleting anything in
KMail until I am like 120% convinced all is good) and those remain unreadable.

Am not sure if I should file a bug and in that case actually "on what and how"