When I open kdenlive and restore a recent project, the thumbnails of the clips in the project bin is not displayed. When the clips are re-loaded, the thumbnails show up normally.
Ah, I had a bad symlink... basically, I symlinked out /home/user/.cache/kdenlive to a larger disk, as I keep my home directory small, and the cache directory of kdenlive is not user configurable in the UI.