If he was mistaken, then all the people who accurately quoted him would have wrong information too. Mizanu'l-ai`tidal, a book on the [life sketches of the] narrators of the traditions of the Prophet (pbuh) reports that when he was old, Hisham's memory suffered quite badly. (vol.4, p.301-302)
Kama alikosea sawa na watu wote wanao mnukuu kiusahihi nao watakuwa na taarifa isiyokuwa sahihi. Mizanu'l-ai`tidal, kitabu chenye kuelezea [madokezo ya maisha ya] waenezaji wa simulizi za Nabii (amani na iwe juu yake) anaripoti kuwa alipokuwa mzee, kumbukumbu ya Hisham iliharibika vibaya sana (juzuu ya 4, uk.301-302).