I think I found a bug, but can't really reproduce (I had it the first time I used mdlr)
I had a repository with another repo inside it but not declared as a submodule.
I did this:
mdlr init
mdlr add ...
mdlr import -f
And it seems like the import didn't overwrite or work because it was already there.
Then I retried but I first deleted the subrepository and it worked fine. I can't say more :P