Here’s a portion of the safety recall report, which describes the issue:
In case of fuel tank heavily overfilled and in particular handling conditions, liquid fuel could reach the carbon canister. If purge valves are reached by fuel this could affect the functionality of the fuel EVAP system. This is worsened in case of winter fuel usage.
EVAP system components faults could cause fuel vapors not treater properly. With not properly treated fuel vapor, particular maneuvers, as example engine over revving at idle, could imply contact between fuel vapor and hot gasses. Especially if combined with a not approved aftermarket exhaust system this could lead to risk of fire.
Here’s what you should do
Lamborghini has agreed to notify all owners of affected vehicles who will be instructed to take their car in to an authorized dealer. The EVAP system will then be upgraded free of charge.
In addition to the Veneno, the Anniversario, Miura Homage, Pirelli Edition, Super Veloce, and Roadster “whose technology derived from Aventador models” is included in the recall, with production dates ranging from March 2011 to December 2016.
Article source: https://www.technobuffalo.com/2017/02/15/4-million-lamborghinis-recalled-due-to-fire-risk/