Copy-pasted Portals don't work right away

The Version that I am using:

MM 2.1.10

Steps to reproduce the Issue:

1. Select multiple Nodes, some of them being Exit-Portals.
2. Copy-paste (or duplicate) the selected Nodes.
3. The copy-pasted (or duplicated) Node-Setup no longer seems to work.

Solution (and thereby hopefully a Hint towards what the exact technical Issue might be):

It turns out that you have to click on the Exit-Portals and select the correct Portal-Element from the List again. For Example, if I have copied an Exit-Portal "Trees", the newly duplicated Exit-Portal will still read "Trees", but it behaves like an "(Empty)" Portal-Node (even though it reads "Trees"), so I have to click on it and select "Trees" from the List again. After that, the Portal-Node works again.