SDDM Version 24.3.1.351
Steps to recreate:
- Create two tables, with at least one table having a primary key (PK)
- In design properties, add one or more UDPs with no default values and select foreign key check box
- Draw a foreign key from table 1 to table 2
- Right click the foreign key line and select properties
- Select UDP from left
- Update one of the blank UDP values
- Click Apply and OK
- Open the foreign key properties again.
- No values were saved.
This seems similar to a previous bug on column level UDPs:
https://forums.oracle.com/ords/apexds/post/user-defined-properties-values-at-the-column-level-don-t-sa-1305
Note: setting the FK with a transformation script does save the update.