'No document' in Mediaset

Hi,
To build the Document DB in foundry, I uploaded the PDF files to multiple mediasets.
After uploading thousands of PDF files, I discovered that some pdf files could not be previewed with message “No document” . (around 5% of the files)
image

This is ramdomly happend among the mediasets. This seems not the problem within the PDF files. And I did not encounter any error message
during the upload.
Any solution for this?

Our team has discovered that the file name contains comma(,) has this issue. If you are experiencing same problem, remove the comma(,) in the file name.