Reproduction

1. Create a library with 2 versions: V1 and V2
2. Create a book
3. Create a version in the book
4. Once the version is saved, add a library reference configuration
5. Add the library created at step 1 and save the value
6. Edit the library version reference

Result

No suggestion is provided

Expected result

V1 and V2 are provided as suggestions

Workaround

Start typing the name of a version ("V" here) and the corresponding list will be displayed.