I created using pimdataexporter a full copy of the pim information on my
Tumbleweed account. I tried to import this on my account on a new Leap 15.5
system.
In KMail I found two Local Folders with two different Maildir folders, one in
~/.local/share/0/akonadi_maildir_resource_0 and the other in
.local/share/akonadi_maildir_resource_0
The first one is the one I have on the Tumbleweed system.

In my view this import should create only one Local Folder with the content of
the local folder from the import.