enabled =/= visible, at least in master branch there are various panels that are not available unless you set parameters to enable them, then you can make them visible from that context menu. Compare the context menu on your clean config and your vert ui config and see if there's a difference in the panels available. Also one could have the combo view option while in another you have tree view, property view and task view separated.
Actually, no need to, I've just checked myself first with a clean config: then after importing vertical UI config: There is no bug, you just have a different config with a different set of panels available.