Replication:

Note: All redacted content will appear as xxxxxx.

1. Add git repository in SourceTree
2. Press the Terminal button in the toolbar (Image: http://i.imgur.com/VxJ4RBt.png)
3. Add git subtrees using the following command in Terminal:
   #!/bin/bash

   git subtree add --prefix modules/xxxxxxxxxxxxxxxxxxxx https://xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx master
   

4. Push branch to origin using Terminal:
   #!/bin/bash

   git -c diff.mnemonicprefix=false -c core.quotepath=false -c credential.helper=sourcetree push -v --tags origin refs/heads/feature/modules:refs/heads/feature/modules
   

5. Quit the Terminal and reload the git repository in SourceTree
6. Show 'SUBTREES' category in SourceTree sidebar

Expected:

Should see a list of subtrees in the SourceTree sidebar

Actual:

Did not see any subtrees in the SourceTree sidebar (Image: http://i.imgur.com/Z8Mvy7T.png)
The .git folder in the git repository has been attached. Note: All redacted content will appear as xxxxxx. The .git/objects folder has been deleted for security purposes.