2006 FEH gas gauge drop after fill-up
 

Hi all, new to the forums and also new to hybrid. Just got a used 2006 FEH and for the last two fill-ups, first it shows about 440 miles to E then after driving it for 30 - 45 miles and parked overnight, and when I start the car in the morning the gas gauge will move about 1/8 inch to E (but it was full the night before) and the miles to E change from 400 to 360 miles to E. ?? Does the car has gas leak? It should continue from when it was left off. The miles to E becomes stable after the initial drop, and the gas gauge movement also behave normally. I park the car inside a gate so there is no way if someone will steal the gas from the car. Does anyone has seen this problem? I wonder if there is leak somewhere and once it reaches to certain level, it won't leak anymore. Does it make sense? It average about 350 miles it says "Low in Fuel".
Thanks