Conor McGinn and Holly Lynch resigned their posts following the sacking of chief whip Rosie Winterton in a reshuffle that plunged Labour back into turmoil.
But sources close to Mr Corbyn hit back by branding St Helens North MP Mr McGinn “disloyal” and insisted he jumped before he was pushed.
A Labour source said: “No-one will lose any sleep over Conor McGinn resigning after the disloyalty he showed in organising resignations during the attempted coup.”
The removal of Ms Winterton provoked an angry backlash, with chairman of the parliamentary party John Cryer writing to MPs to protest that he and the chief whip had been kept in the dark about the reshuffle despite being engaged in talks with the leadership on putting some of the posts on the shadow cabinet up for election.
The resignations come in the wake of controversial choice for shadow attorney-general Shami Chakrabarti comparing the Labour Party to a “war zone”.
And the walkouts follow reports that leading anti-Corbyn figures are preparing to organise their own “shadow shadow cabinet” in direct competition with the official front bench, which will produce its own set of policy initiatives.
The senior moderate in Mr Corbyn’s top team expressed a relaxed attitude to the emergence of such a body.
Shadow Brexit secretary Sir Keir Starmer said there were “unresolved” issues in the parliamentary party after Mr Corbyn’s reshuffle, a shake-up which saw Labour plunged back into infighting.
Asked about the “shadow shadow cabinet” on the BBC’s The Andrew Marr Show, Sir Keir said: “There are unresolved issues in the Parliamentary Labour Party (PLP).
“We do need to resolve them as soon as possible. We need to be an outward-looking, confident party rather than an inward, divided party, so we need to address that.
“I respect colleagues who want to make their voice heard from different places, whether it’s the backbench, the mid-bench, through select committees, or on the frontbench.”
Sir Keir, one of only a handful of the 63 people who quit the shadow team in protest at Mr Corbyn in June to return to the frontbench, sidestepped directly answering when asked if the Labour leader would make a good prime minister.
The Brexit chief also appeared at odds with Mr Corbyn as he called for a reduction in immigration numbers after the Labour leader refused to bow to pressure from MPs to do the same at last month’s party conference.