You set the combo number?
And what number are you setting there?

The Combo ID number of a combo that looks like a pit?

Don't be doing that.

What you want to do is make all of your pits have the combo type number (so, 35 for centre statue) that is set in that box.
Centre Statue is default.

So don't make your pit combos blank propertywise, and don't set an absurdly high value in that box, because it ain't a combo ID.

That doesn't solve the dissapearing FFC problem though.
Hrm.