We appreciate you writing in. I am not sure about the cause of this issue. However, you can try this steps:
1. Quit premiere.
2. Move your files to a NEW folder on your hard drive.
3. Launch premiere and relink your files. Here's how: https://helpx.adobe.com/in/premiere-pro/using/relinking-media.html
You can try the same for Premiere Rush and let us know if it helps.