I would just do 'for each "ghost"'+'"eaten" is playing' + 'trigger once' = find path to ghost home. Or maybe link it to the event that kills the unit. So like: '"ghost" health =< "0"'+'trigger once' = 'find path to ghost home'.
How you have it now will continue to loop the pathfinding. Even if you add trigger once to what you have, it will still loop because as soon as it finds a path it is no longer finding a path and the animation is still playing.
If your pathfinding is failing, it could be that you have the cell sizes too large, meaning they can't fit through the gaps. Try lowerig it to something ridiculously small like 2 and see if it works then.
Also a capx can really help us to debug ;)