Though the last update may have affected things it has nothing to do with the lack of ghosts or invaders,

This happens regularly, including every day for the 24hr only ghosts and invaders ,and when the time of these things run out at the same time, especially at the start of a kingdom event its more problematic .

I think you will find that the situation only disadvantageously affects those of us who use the web based browser game.

 Though of course that it sometimes can work in your favour ,It is annoyingly true that you can move to another kingdom and find they have no targets,when your home kingdom does.