There is a bug in the copy and paste of Blox.
If you copy a "structure2 in the diagram and paste it, visually everything seems fine,
but when you save it and afterwards load it again, the links are not restored as it should be.
The pasted links appear "above" the original links connecting the original blocks.
Obviously the internal connection of the linkpoints is not changed as it should while pasting
I might give more detailed information a little later.