Occlusion problem Various mesh disappear

Hi, i just move to 4.14 my project and i’m having issues on only one map, sadly it’s the more complex of the game, only in a certain point of the map some level mesh keep disappearing i built the visibility using the visibility volume but i’ve got the same result as when the visibility is not prebuilt, any help direction or tutorial link would be appreciated :slight_smile:
Thanks in advance.