Moving git tag with "Push tag" option checked will cause error ''tag already exists on the server'.

Steps to reproduce:
1) Tag a commit on Sourcetree and push tag into remote repo.
2) On Sourcetree, right click the existing tag, check the "Push tag" option and select the repository, open advanced options and check "Move existing tag"
3) When clicking add, an error message stating that the tag already exists on the server will occur.

Workaround:
Select only "move existing tag", but NOT "Push tag", then use the git command line to execute:
git push origin --tags -f