I can confirm this. I had a air node with a shrine on it at my first city cast corruption on it destroys shrine and converts it to death mana node as it should but now it will not permit a shrine to be built on it. Tried going back to earliest autosave the shrine was already under construction but far from finished same result with death mana node created but unable to build a shrine on it. Unfortunatly there does not seem to be anyway to demolish a shrine like you can with buildings in your cities. Have not tested yet with a node that has not begun shrine construction yet.    ...  Tried corrruption spell on plain node no shrine on it or building it seems to work ok in this case. Still needs to be fixed so can switch nodes with shrines built