You can check the database settings.
The documentation says under CA PPM installation
https://docops.ca.com/ca-ppm/15-5/en/installing-and-upgrading/install-ca-ppm#InstallCAPPM-ConfigureaDatabasewithMicrosof…
MS SQL Server
Review the Imported SQL Server Database Options
Important! Mixed collations settings are not supported. If you change the server-level default from SQL_Latin1_General_CP1_CI_AS to another collation, create a new SQL Server instance with the correct collation SQL_Latin1_General_CP1_CI_AS before creating the CA PPM database
For Oracle
Complete the following tasks in the order presented to configure Oracle for use with CA PPM.
For extended character handling on an Oracle server, set the NLS language to AL32UTF8.
UNIX: Edit the UNIX user profile to add the NLS_LANG variable:
NLS_LANG=AMERICAN_AMERICA.AL32UTF8
EXPORT NLS_LANG
Windows: Start the registry editor:
From the Start menu, select Run, and enter regedit.
Go to HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\<Oracle Home> and change the value for key NLS_LANG to:
AMERICAN_AMERICA.AL32UTF8
Set the required parameters in the following table for your new database:
Name Value
Character Set AL32UTF8
National Character Set UTF8/AL16UTF16
nls_date_format YYYY-MM-DD HH24:MI:SS
nls_sort BINARY
nls_comp BINARY
query_rewrite_enabled true
Cursor_sharing FORCE
Does the problem occur everywhere where you use äöü and for all users using them?