Webclient shows contacts which are not visible in app

[ontheair81]

Expected Behavior

When beeing invited to a group, members from this group are not automatically added to the local contact list in the Threema App. They also should not be visible in Threema Web.

Current Behavior

The app is working as expected. The group members are not visible in the contact list in the app. But they are visible in Threema Web.

Steps to Reproduce

1. I was invited to a group chat (last year) with a lot of people I did not know before.
2. All these people have been added to my contact list in the app automatically (as this was the standard behaviour of the app months before).
3. Then there was an update of the app, which changed the mentioned behaviour: Contacts from groups will not be added to the contact list anymore, but existing group contacts stayed there.
4. I left the group (months ago) and deleted all the contacts of this group manually in the app. None of them have been linked to my adress book before and with none of them I had chats outside of the group.
5. When looking now at the contact list in Threema Web, all these old and deleted contacts are still visible there.

Note: I am not 100% sure if this bug is reproducible nowadays. Its a description of what happened and why I see more contacts in Threema Web than in the Threema App.
This bug report was created at advice of @dbrgn (https://threema-forum.de/thread-2908-post-40463.html#pid40463).

Your Environment

• Threema Web version: 2.1.0
• Threema App version: 3.54.2000444 (Android via Google Play)
• Browser name and version: Firefox 62.0.3, 64 Bit
• Computer operating system and version: Linux Mint 19, Windows 7 Pro
• Smartphone operating system and version: LineageOS based on Android 7.1.2