I merged a PR with the GitHub web interface, which resolved in a successful merge commit.
Afterwards, GitHub is complaining This branch has conflicts that must be resolved. Does anybody know why or how to get the status merged?
You'll need to update your branch with new commits from master, resolve those conflicts and push the updated/resolved branch to GitHub.
git checkout master
git pull
git checkout <branch>
git merge master
[ ... resolve any conflicts ... ]
git add [files that were conflicted]
git commit
git push