New versions of Git have the AVH Git Flow version.
The biggest issue is that the Source Tree version merges release branches in different way:
The Git (AVH) Git Flow merges release into master branch, tags it, and then merges master into develop.
The SourceTree merges release into both master and develop branches, making version tag unreachable from develop branch.
This makes the Source Tree Git Flow version incompatible.
There are at least 3 other issues on this problem:
https://jira.atlassian.com/browse/SRCTREE-1762
https://jira.atlassian.com/browse/SRCTREEWIN-1394
https://jira.atlassian.com/browse/SRCTREE-2052