When viewing the Jenkins dashboard or a folder, the build queue appears correctly (Dashboard_WithPlugin.png). Once I view a multibranch pipeline, the build queue disappears (MB_WithPlugin.png). If I disable the Simple Queue plugin, I can see the build queue on the very same page (MB_WithoutPlugin.png). If you click to collapse/expand the build queue, the items in the queue will appear briefly, but disappear after a few seconds.