[Bug]: Federation: "Allow download and sync" cannot be checked

[gdnmhr]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When creating a federated share, the "Allow download and sync" option is ignored and cannot be checked afterwards.

On Nextcloud 30+ this prevents previewing and downloading any files from the remote server (see also #48954).

Steps to reproduce

1. Establish a mutual federation between two servers
2. Share a folder with someone on the other server, ensure "Allow download and sync" is checked
3. Observe that "Allow download and sync" is unchecked afterwards
4. Try to check "Allow download and sync" later

Expected behavior

Checking "Allow download and sync" should allow the user on the other server to preview and download these files.

Nextcloud Server version

30

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Nginx

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response