When importing images using drag & drop, all images in folder are checked?

When you import a number of images from a specific folder using drag & drop, the whole folder is checked for duplicates. Does anyone know why this happens? And is there any way to limit the duplicate check to the photos that are being imported? (I've tried deselecting "Include Subfolders" and it makes no difference.)

(Capture One 21 14.0.1.7)