Corbyn began rebuilding his team last month with the recruitment of Jonathan Reynolds as the new shadow city minister, and has since made a raft of new appointments.
However, this included a new chief whip in the shape of Nick Brown, replacing the incumbent Rosie Winterton.
And while Labour sources say Conor McGinn and Holly Lynch had expressed a desire to focus more on family and constituency issues, respectively, both were known to be close to Winterton.
A spokesman for Mr Corbyn said: "We thank Conor McGinn and Holly Lynch for their services. Their positions will be filled in due course".
Among other appointments, Corbyn also handed a promotion to key ally Diane Abbott, who steps up from her role as shadow health secretary to a new brief as shadow home secretary.
Former rebel Sir Keir Starmer also joined the shadow cabinet to serve as shadow Brexit secretary, while Baroness Shami Chakrabarti - ennobled months after completing a report into antisemitism in the party - joins as shadow attorney general.