Map Nodes Not Connected

I (along with many others apparently) seem to have run into the issue where clusters of map nodes are inaccessible. Single nodes, too. It always seems to happen with nodes that are of greater value on my map, i.e. the moment of zen node.

+1 encountered this for the first time. A section of nodes with "a moment of zen" is its own little island with no connections to other nodes.

Edit: adding image.