New added movie is marked as watched

Hi guys,
I have a problem on my HTPC (Win10) with Kodi 17.1. When I add new movies to the folder where the movies are scanned after Kodi startup – these new added movies are marked as already watched. It means I have to search them in the library and mark them as not-watched. It is very annoying for me Sad do you have any tip how to manage this issue?

Thank you very much in advance for your help!
Martin