Sulayman bin Mughira said that Ibn Umar bin Abu Salama is mursal.
حدثنا عفان حدثنا جعفر بن سليمان عن ثابت قال حدثني
وقال سليمان بن المغيرة ابن عمر بن أبي سلمة مرسل
Its isnad is sahih. Ahmad here relates from Sulayman bin Mughira that the son of Umar bin Abu Salama did not hear from his father. Others, however, have established that he did hear from him.