After upgrade to Sourcetree 3.2.5 [6 Aug 2019]
There are some differences with before where use push to origin function.
Before:
It will auto fill the Remote branch text-box with my new local branch name and can click Push button to push to origin
Sourcetree 3.2.5 [6 Aug 2019]:
It will leave it blank and click Push button will produce error.