I can't remember having see this issue addressed with a solution by Pocus. Even if my memory might be failing--(Error: DIMM MB/P0/Ch1/D0: ecm errors exceed acceptable limits

)--, it's obvious that the issue is still present.
Being that Pocus seems to have his hands full with WON at the moment, I wouldn't expect to see a solution in the foreseeable future.
I wonder, can the South still see Buchanan in his unit lists? Does the North see him?
Can the North move Buchanan outside of a Union stack normally? Remember, leaders have detection value of 0, so a leader in a region where you otherwise have no detection value (friendly loyalty, friendly units nearby) is invisible and can only be selected through the unit list.