Material in Blendables in PostProcessVolume shows different in VR mode

Hi there,
I’m currently experiencing a weied problem when using material in blendables in PostProcessVolume.

As you can see in the pic above, this is should be the correct look and it does so in the PIE mode. But when I preview in the VR mode, it only shows only a part of it (show as below).

It is the same as what I can see in the HMD. After I quit the VR mode and back to editor, the wrong scene remains.

I just add the material in the blendables. Has anyone else had such a problem and how I can fix this. Thanks.