I am using Sourcetree v3.4.9 (latest), but this also happened on whatever version I just updated from.
When I try to clone a remote repo from my Bitbucket account, and I tick Show Organization Repos, the dropdown appears for selecting a workspace... but all entries are blank. They are obviously there, as if I select an item on the list, the repos are filtered as if I had selected the workspace.

Anyone else have this issue? Any fixes?