Our naming standard for feature branches is:

feature/{developerinitials}/{yyymmdd}_{ticket}_description

We also use the git-flow feature in SourceTree to create and manage those branches.

Starting in 3.1.3, when we try to create that branch through git-flow, we get the error:

The name is invalid. Ref names must follow git ref-format rules:
https://www.kernel.org/pub/software/scm/git/docs/git-check-ref-format.html
Additionally Sourcetree does not support the use of '/' in Git-flow branch names
Completed with errors, see above.

I presume you had a reason for changing this, but it was working before, and it's annoying that it has stopped working now. If we have to give up git-flow or our naming standard, we're going to give up git-flow (it's much less annoying to scroll past a dozen folders than a thousand branches), but we'd prefer not to have to give up either.

Please consider changing the behavior back to what it was before.