[Bug]: Error while synchronizing if ends with an `x`

⚠️ 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 synchronizing to the Nextcloud server, directories with a special syntax are not taken into account:
There are several subdirectories in the directory with a "lastname,firstname ()" naming scheme. Every time the first name ends with "x", the synchronization stops with the error message "forbidden..."
If I replace the x with another character or add another character, the synchronization works.

Steps to reproduce

1. Rename a Subdirectory on a Client (Windows 11) to "lastname,firstnamex ()" - so that the firstname ends with x
   2.syncronize with the Server
   3.synchronization stops with the error message "forbidden..."

Expected behavior

the subdirectory will be ignored

Installation method

Community Web installer on a VPS or web space

Nextcloud Server version

27

Operating system

Other

PHP engine version

PHP 8.0

Web server

Apache (supported)

Database engine version

MySQL

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

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

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

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response

No source file or test is identified. Start by reproducing the failure with a Windows 11 client using a directory named "lastname,firstnamex ()" against the stated Nextcloud 27 setup, then trace the synchronization path that returns the "forbidden" error. Done means synchronization completes while the matching directory is ignored.