Creating shares for files/folders not possible from one domain when in trusted_domain config

Nextcloud version: 18.0.2
Operating system and version: OpenSuse 15.1
Apache or nginx version: Apache 2.4.33
PHP version: 7.2.5

I’m using NC in trusted_domain setup, e.g.

'trusted_domains' => 

array (
0 => ‘cloud.domainA.tld’,
1 => ‘cloud.domainB.tld’,

I have a (my maily used) user, let’s call him userA, created when logged in via cloud.domainA.tld.

  • When this user is logged in via cloud.domainA.tld, he can create and use any shares, files and/or folder, following my settings. E.g., important for me, sharing a folder and it’s subfolders to a specific group.

  • Users created belonging to this group, logged in via cloud.domainB.tld, can use these shares. FINE!

BUT: When I log on as userA (just tested: or any other user) via cloud.domainB.tld, I can click on the “share” symbol, sidebar pops up with file/folder properties, but only tabs “Activity” and “Comments” shown, NOT tab “Sharing”.

Anythiung I’ve missed? Secret config option? RTFM?
Or a bug?