Gameobjects disappear in front of camera when using occlusion culling

Unity Engine
1

I build a scene with a lot of rooms and use occlusion culling for optimism.
But the wired things happen to me. The gameobjects in front of camera just were culled. The two screenshots below will show this circumstance.
I have no idea with this problem, can anybody help? Thank you!!!

1640644--101753--$1.jpg
1640644--101753--$1.jpg1037×926 119 KB
1640644--101754--$2.png
1640644--101754--$2.png1037×928 132 KB
1640644--101755--$3.png

2

Does it only happen when looking through doorways?

3

Not really, it also happens somewhere else nearby, but only happens in that small area, have not seen it happening in other places of the building .