Is this a bug of the SourceTree in applying Rebase command with conflicting branches, or am I missing something?

This is similar to the question SourceTree – rebase –interactive – Merge conflict aborts rebase with one difference: I am not using --interactive rebase.

Below is what I experienced few times. First I thought it was my fault of resolving conflicts but it looks like a bug/featrue of the SourceTree itself.

Windows 10. SourceTree v.3.4.13

I want to rebase feature branch on develop which have conflicts in few commits. Steps to reproduce:

1. Check out feature branch
2. Right-click on the develop branch and select Rebase current changes onto develop
3. Window pops up: You now have merge conflicts in your working copy that need to be resolved before continuing ... . Click Close
4. History view shows: Uncommited changes (detached head)
5. Click on it. Some files from the conflict commit of the feature branch appear in the Staged files area and some in Unstaged files
6. bash-git terminal shows $ (feature | REBASE 1/2) (I have 2 commits in the feature to rebase)
7. In the Unstaged files select a file with conflicts. Right-click on it and select Resolve using 'Mine' ( in this case ‘Mine’ is develop – branch I am rebasing onto) –> conflict is resolved
8. Select ‘Actions -> Continue rebase’
9. Window invinting to edit the commit message appears. Content: message from the feature first commit plus comments:

first commit message

# interactive rebase in progress; onto 8d27b323
# Last command done (1 command done):
#    pick 1815a5f7 first commit message
# Next command to do (1 remaining command):
#    pick 9708e11b second commit message
# You are currently rebasing branch 'feature' on '8d27b323'.

10. Click ‘Ok’
11. Window closes. In History branch feature appears on top of develop with only one commit ! first commit message
12. Another window pops up: You now have merge conflicts in your working copy that need to be resolved before continuing ... .
13. Click Close
    Nothing happens!
14. The second commit second commit message does not appear in the rebased feature branch.
15. Changes from the second commit are not applied
16. Terminal shows that rebase has finished: $ (feature)

Why was the second commit not rebased?
Is this a bug of the SourceTree?
If not, what is the right process in SourceTree to do rebase with conflict resolution?

Thank you,
Dmitry