Well it doesn't vanish… esp because its pretty much complete. It immediately will be brought up in a Senate confirmation and is a reason why he won't be confirmed 

Cje95

But the larger impact of the resignation is that the House Ethics Committee investigation into Gaetz, which was in its final stages, will be effectively dead. The panel will have no jurisdiction to investigate Gaetz since he is no longer a member of Congress, and its findings may never see the light of day — a major boon for Gaetz as he prepares to face an already-skeptical Senate.

Basically, he was two days away from the internal ethics report being released, and now he's not in congress, so the report vanishes.

Politics_And_Law

Gaetz Resigns from Congress Effective Immediately After AG Nod

>But the larger impact of the resignation is that the House Ethics Committee investigation into Gaetz, which was in its final stages, will be effectively dead. The panel will have no jurisdiction to investigate Gaetz since he is no longer a member of Congress, and its findings may never see the light of day — a major boon for Gaetz as he prepares to face an already-skeptical Senate.

Basically, he was two days away from the internal ethics report being released, and now he's not in congress, so the report vanishes.