(Not the real cause, read the Update below)
Just narrowed down the cause and found that when two consecutive adjustment layers exist, it will cause layers below failed to export correctly (become full size empty image). When delete one adjustment layer from the sample PSD, things begin to export correctly.
Note: using Adobe PS CS5 + latest PS Export script.
Exported images:
Sample PSD:
ExportSample.zip
Update:
Just did a little more testing and found out that the cause is not that double adjustment layers although deleting one of them solve the issue. The real cause is the PSD having a group Clipping on a pixel layer below. The PSD is saved from ClipStudioPaint which support it but PS does not support group to have clipping mask (at least the CS5 version). So nothing really need to be done but a warning would be helpful if this can be detected so that when other user run into the same situation they will know whats the problem.