Here and Now

Here and Now is a Fallout 2, Fallout 3, Fallout: New Vegas, Fallout Tactics, J.E. Sawyer's Fallout Role-Playing Game and Lionheart perk.

This perk "grants an additional experience level with all advantages that entails" - Except one advantage. The level you just gained has no perk, as Here and Now effectively disappears after giving you another level.