That might be the issue. I would look to open up a case with AWS quicksight.
I wonder if there is a way in the Manifest file to exclude certain types of files like that. However, I don’t know if you can and couldn’t find any documentation for that specific use case.
Here are the steps to open a support case. If your company has someone who manages your AWS account, you might not have direct access to AWS Support and will need to raise an internal ticket to your IT team or whomever manages your AWS account. They should be able to open an AWS Support case on your behalf. Hope this helps!