Pressure Differential Scanning Calorimetry (PDSC) has been used to study the conditions of formation and disappearance of double peaks in the absorption and desorption of the LaNi5-H-2 system during thermal cycling. Thermal absorption-desorption cycling reveals double-peak formation both in absorption and desorption phases. Splitting of a single peak into a double-one is induced below 60 degrees C even in case of absorption. The double peak disappears, due to annealing at moderate temperatures in a hydrogen atmosphere, easier in absorption than in desorption. It reappears, however, easily when thermal cycling is continued.