Grading: Its chain is sahih.
Technical note / Defect ('illah): Here Humayd means "Humayd al-Tawil".
Reference / Source: Imam Ahmad narrated it at (12916) from 'Abd al-Rahman bin Mahdi and at (13691) from 'Affan bin Muslim, and Ibn Hibban at (2493) via Yazid bin Harun; all three narrate it from Hammad bin Salamah with this same chain.

Reference / Source: Imam Ahmad narrated it at (13121) from Mu'adh bin Mu'adh and Ibn Abi 'Adi, and Ibn Hibban at (2587) via Isma'il bin Ja'far; all three narrate it from Humayd (al-Tawil).
Technical note / Defect ('illah): None of them mentioned, through Humayd, the woman's name as "Hamnah"; rather they said "so-and-so" (a woman).

Reference / Source: Ahmad (11986), Muslim (784), Abu Dawud (1312), al-Nasa'i (1308) and Ibn Hibban (2492) narrated it via Isma'il bin 'Ulayyah, and al-Bukhari (1150), Muslim (784), Ibn Majah (1371) and al-Nasa'i (1308) via 'Abd al-Warith bin Sa'id; both of them narrate from 'Abd al-'Aziz bin Suhayb.
Technical note / Defect ('illah): In all these narrations the woman's name is given as "Zaynab", except for one narration of Abu Dawud in which Harun bin 'Abbad (a narrator "mastur al-hal", of undisclosed condition), among the students of Isma'il bin 'Ulayyah, deviated (shadh) and mentioned the name "Hamnah" instead of Zaynab.

Important point: Al-Hafiz Ibn Hajar tried in "Fath al-Bari" 4/ 365 to reconcile these two narrations, but his discussion is unconvincing; you may look at it there if you wish.