If you had a slow leak, it may not be gone.
But the high-pressure gauge is temperature dependent and no indication of the tank fullness until it hits the red zone.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk