for some reason i was playing the campaign mode and in the mission Conservatory.
when you need to defead the wave’s off Skimmers there was only 1 wave and after that notting was coming and i wait 10 mins and still notting was coming.
after i exit the campaign and restart the same campaign file the wave’s have been comming like it has to be done.
and its not the first time i have this problem more on some other place’s.