A bug? Mail.app v6.3 shows duplicated addresses in mail-to autocomplete when two iCloud accounts are active

I use TWO iCloud accounts to share addresses (contacts) with a second person (iCloud account).

Since I have this set up, the autocomplete of Mail.app lists Email addresses that are in "shared/linked contact cards" twice.

In addition, the arrow-down function to select one of the several Email addresses that Mail.app offers after typing a few letters of the name does not work any more. It is not possible to "move" over the duplicated preselection entries.

I am sure is it (another) bug! Not fixed in 10.8.3.

Is there hope for 10.8.4?