There is a (minor) difference in the behavior of the concat2 node in MoI4beta.
It is a failure to release the mouse attachment to the node, under certain circumstances.

By clicking RMB on top of the concat2 node, one of three input configurations may be selected,
called Numbers, (numarray), Points, (pointarray), or Objects.
This should be done before attempting to wire the input with the wrong type.
In MoI4beta, "Dragging" a gold wire for Objects to the wrong input, Numbers or Points, and then pushing RMB and selecting Objects,
results in the proper input being changed to, and the wire attaches, but the mouse is then locked onto the node box.
The only way I've found to release the lock is to press ESC, and reload the file.

This does not happen in MoI3. Clicking the RMB releases the attempt to wrongly attach the wire.

- Brian