How bad is it if training and validation data overlap in a student ML project?[D]

Excerpt

I’m working on a student machine learning/computer vision project and recently realized that my validation set was not completely independent from my training set. The project is more focused on comparing different experimental conditions rather than maximizing benchmark performance, but I’m concerned about the implications of this oversight. From a research or academic perspective: How serious is train/validation overlap in a student project? Does it invalidate the entire project or mainly affe