Are there currently any live/known issues with images not rendering while previewing a PDF?
Hope you are doing well. Per the description, I understand that you want to know about known issues with the rendering of files.
Files not rendering images could be due to multiple reasons. The reasons can comprise of the way the file was created, the data stored within the PDF which could cause the issues and a multiple number of other reasons.
Until we know of or get the file to test, we will not be able to provide a concrete solution to why the issue happens.
Hope this clarifies your question.