End-to-End Encryption not working propably on Android

I’m using a Google Pixel 3 with the up to date Nextcloud Client.

I’ve enabled the end-to-end encryption. How did I do that? I logged into my Nextcloud via Browser and activated / downloaded the e2ee app. After downloading the app I’ve closed the browser and opened my Nextcloud client. The client gave me a passphrase which I saved. Then I created a folder, opened my client, right clicked the empty folder and clicked on “encrypt”. Encryption process went fine on my Desktop and I could access my folder on my Android after typing in the passphrase. Problem is that my folders are empty. I have to upload a picture in that folder first to see all my photos on my Android device. Another problem is that the image in that folder get duplicated and if I click on them they can’t be opened. Download error. But if I click on the 3 bars in the Android client and choose “pictures” all pictures will be loaded.

Is that a bug? Anything I forgot?