Version:           1.9.6 (using KDE KDE 3.5.8)
Installed from:    Ubuntu Packages
Compiler:           I used the precompiled package from the ubuntu repository
OS:                Linux

I prefer to stick to the keyboard when working, so when I go to create a new message, I hit Ctrl-N in Kmail and start typing the recipient name in the To field.  In the dropdown box, the first three of my most frequently used recipient addresses are in the format:
    "lname, fname" <user@domain>

When I use the down arrow key to move to the second or third address in the list, the lname part from the first address is left in the address field and the second address replaces the remainder.  So, when the second address in the list is highlighted, I get the following in the address field:
    "lname, "lname2, fname2" <user2@domain2>

Only the portion after the last comma on the line is replaced.  This happens on the next address; if I hit the down key again, I get:
    "lname, "lname2, "lname3, fname3" <user3@domain3>

If I then hit the up arrow key, the address then becomes:
    "lname, "lname2, "lname3, "lname2, fname2" <user2@domain2>

When I hit Ctrl-Enter to send the message, I usually will get a bounce message because lname@localhost is not a valid user on my system.