When adding a duplicate branch permission, an error message shows that has a link to allow you to click through to the existing permission. When using a branch pattern, it's necessary to click twice to activate the link. (Presumably when the pattern field blurs the click is prevented from propagating or something of that nature)
- Create a branch permission with a pattern value of "my-branch-pattern-here"
- Create a second branch permission and set the pattern value to "my-branch-pattern-here".
macOS; Firefox 72, Chrome 79, Safari 13
Clicking once on the "Edit existing permission" link will activate it and show me the existing branch permission to edit.
Need to click twice on the "Edit existing permission" link to activate it. (It's not strictly necessary to click twice on the link, just one click outside of the pattern input field and then on the link will work too).
Note too that if you click outside of the field, then back into the field, you can then click the link as well.
None necessary, clicking twice on the link is the "workaround"