Multiple Accounts; App mixes login credentials

Expected behaviour

Separate accounts, which have different credentials. Switching accounts. App is only fetching information from the currently selected account; uses only the credentials of the current account

Actual behaviour

I'm running to accounts. One username is "strubel". Other nextcloud domain & installation, the name is m.strubel.

On the domain using "strubel", I see error messages from fetching an avatar or other informations:

192.168.56.107 - strubel [18/Sep/2020:20:31:27 +0200] "GET /nextcloud/index.php/avatar/m.strubel/128 HTTP/1.1" 404 2 "-" "Mozilla/5.0 (iOS) Nextcloud-iOS/3.0.6"

Worst case, the happens with login credentials and the nextcloud instance/fail2ban blocks your IP. (happened twice to me).

After switching, it is not possible to use the switched-to account correctly.

Steps to reproduce

use two nextcloud instances, different domain (maybe), different login credentials.

Reasoning or why should it be changed/implemented?

Fixes are nice :-)

iOS version

14.0 (maybe happened earlier, too)

App version

App, Nextcloud Coherence for iOS 3.0.6.8 @ 2020

Server configuration

not relevant, because the URL requested is already wrong

Nextcloud version: (see Nextcloud admin page)
18.0.1 & 18.0.7

Reproduce the issue with two Nextcloud instances and different credentials, then trace account switching and the requests made when fetching avatars or other account information. Confirm that requests after switching use only the selected account's instance and credentials, including the avatar request shown in the report.