Persistent Clip Problems on opening project

Every time I open my kdenlive project, I am greeted with a popup window listing “Clip Problems”. It is basically a list of all the video files in my project, listed as Type: Unreferenced Clip, and Status: Fixed. A backup file is created every time I save the project. But upon reopening, the popup reappears.

Opening a large project is tedious, because it takes very long to redo all the pending jobs, and backup files are now cluttering my folder. There is probably some kind of corruption in the file, that I cannot pinpoint nor remove. Saving as new project does not make the problem go away.

Any ideas?

Klaas