LoP conundrum

Refuting the government's accusation that the Congress had not honoured the "deal" to break the Rajya Sabha logjam, party leader Anand Sharma emphatically stated that he was the "acting Leader of Opposition" and he had not made any such deal.

Sharma is the officially designated Deputy Leader of Opposition in the Rajya Sabha. Ghulam Nabi Azad, the designated Leader of Opposition, is busy campaigning in Jammu & Kashmir. Acting Leader of Opposition? Is there such a post? We are confused.