Every project has same thumbnail

I duplicate projects as I often use the same elements in the same order, but I will import all-new video files and delete the video files from the previous project. However, all of these duplicated projects continue to have the same project thumbnail - the thumbnail that shows when you open Rush to select a project. I am not talking about rendering video and the generated preview thumbnail (this works as it should), but the working project file's thumbnail under "your projects".

This is a minor thing, but it makes it slightly confusing when I go to open a file, as they all have the exact same thumbnail as the original project. Once inside the duplicated projects, there is no trace of that original video content, given I deleted it a while ago.... I am confused about why this is happening.

How can this be fixed, so that duplicated projects will reflect their actual video content in their project thumbnail? Thanks!