Subject: Apache Isis fixture doesnt make relations

I have made two fixtures of two entities (company/empresa) and (worker/trabajador). Both are related, every "worker" must have one "company". After runing both fixtures, the problem is that parented table "company" doesnt show "workers" and I noticed in DataBase that the column "trabajadores_integer_idx" remains in "-1" instead of "0" as it should be.

Any help will be appreciated.
I couldnt find any working fixture with two entities relationed.
Apache Isis version: 1.17

You can check fixtures classes in our Github repository: