Packaging Results in "Corrupt Data" Message

I get this error every time I try to package my project:


In the output from the packaging, a texture or material will be printed last in the list. When I delete the last listed asset and try again, the last printed item is another asset, which I assume means I took care of the “corrupted” asset. These assets work just fine and don’t cause any issues though. I can’t forever just delete random assets like this. What is causing all my packaging problems?