After updating Sourcetree to 2.7 the stash operations don't seem to function properly.

I tried deleting an old stash, it disappeared from the list but later reappeared.

When I tried to pop one stash I got this error:

git -c diff.mnemonicprefix=false -c core.quotepath=false -c credential.helper=sourcetree stash pop stash@{0}
One or more of this task's arguments is invalid. They cannot start with '-', and must follow git ref-format rules: https://www.kernel.org/pub/software/scm/git/docs/git-check-ref-format.html
Completed with errors, see above