What version are you running?
release-4.0.x @ac9782805
The user column recently had some updates, and there's now some dead code. We can get rid of the "user_url" assignment in UsernameColumn.render_data. See https://sonarcloud.io/project/issues?id=reviewboard&issues=AWDsgs8iikuHJGLsZjhp&open=AWDsgs8iikuHJGLsZjhp for the actual code.