Photo View not working

Hello NC-Admins,
I´m using NC 18.0.4 on a Linux based System ( OS: ‪Ubuntu 18.04.4 LTS‬ ).
Everything is working fine. But, when I share a Folder with the Link (not sharing with an exiting User or via e-Mail) with pictures in it and somebody opens the Folder then you can see all Files with their thumbnails. If you open the picture it should open the picture. But in this case you can only see the rolling circle and nothing happens. If you are a registered User or you share the folder via email you can open the pictures.
I´ve tested this wih two different NC installations on different systems it´s the same.
Can somebody confirm this behavior?

Thanks a lot