Rule reminder
When a perception verb appears in reported/indirect speech, the tense shifts back according to normal concordanza dei tempi. In subordinate clauses introduced by 'quando', 'mentre', 'dopo che', etc., the perception verb follows standard tense rules. The infinitive complement of the perception verb itself does not change.
Direct: 'Ho visto Marco arrivare.' → Reported (she said that): 'Ha detto che _____ arrivare Marco.'