Project Panel Thumbnails Not Displaying Properly with Proxies

In Adobe Premiere Pro (version [your version]), project panel thumbnails for clips with proxies appear black by default, although the proxy connections remain intact. When hovering the mouse over the clips, the thumbnails temporarily appear. This issue occurs after renaming proxy files using a bulk renaming tool. Clearing the media cache, switching renderer settings, or importing the project into a new project does not resolve the issue. Playback, rendering, and export are unaffected; the problem is limited to project panel thumbnail display. It seems related to GPU acceleration or cache handling. A screenshot or a small sample project can be provided to reproduce the issue. Immediate attention is appreciated, as this affects workflow visibility for projects using proxies.