This time, Mrs Gandhi hopes to finalise a joint opposition candidate for the vice presidential election next month with the support of the Janata Dal United as well. Along the way, it also hopes to have an opportunity fix cracks in relations between the Congress' Rahul Gandhi and the Bihar Chief Minister that surfaced after Mr Kumar's sided with Ram Nath Kovind.
Lalu Yadav, whose party RJD along with the Congress is in alliance with the Chief Minister called the choice a "historic blunder".
Ghulam Nabi Azad of the Congress too hit out at the Chief Minister, suggesting that Mr Kumar had flexible principles. The Chief Minister was equally unsparing, blaming the Congress, the opposition's anchor, for being slow-footed and losing sight of the big picture. Second-rung leaders in Bihar took the hint and too flung darts at each other.
"We have been all for opposition unity. We had been working for it in the past, and will continue to do so," senior Janata Dal United leader Sharad Yadav told NDTV, refusing to talk any more about the party's stand on the presidential polls.
"Let bygones be bygones," he insisted.
There has, however, been no confirmation on Bihar Chief Minister's presence at the lunch.
For now, the Congress too is making the right noises.
"We have no problem with the JDU. He is the Chief Minister of the Congress party, the RJD and the JDU and we have no problems. We are together, both inside and outside parliament, both inside and outside the assembly," Mr Azad, who is also the leader of opposition in the Rajya Sabha told NDTV.