That's a pretty annoying issue. Since the objectives need to be removed by the mod real soon when the map starts (more specifically at plugin_precache), at the time your .cfg gets executed the objectives are already removed.
The only solution I can see is to to somehow pause/turn off ZP before the map change occurs.
How should I do pause/turn off ZP before the map change occurs?
Has any method? Pleease teach me! Thanks!