As per the community discussion here, when using the "Create Pull Request" item from the right-click menu context on a branch that contains valid special characters (e.g. forward slash / ) the URL of the web based repository service has the slashes double encoded like this:

https://gitlab.com/my-repo/my-repo/-/merge_requests/new?merge_request%5Bsource_branch%5D=release%252Fbranch-name

The %252F should be %2F in the above example, and this is affecting Github, Gitlab and Bitbucket URL's.

This bug was introduced in v4.2.6 and appears to be a reoccurrence of this historic bug: https://jira.atlassian.com/browse/SRCTREE-4819