Since we purchased the 2024 Grand Highlander Hybrid Limited in April 2024, there has been an issue filling the fuel tank completely when the vehicle is on empty. The stated fuel tank capacity from the owners manual is 17.8 gal, however the maximum amount of fuel that can be pumped into the tank using auto fill at the gas station is 12 gal before the pump kicks off. After this, the fuel gauge on the dash reads full, however fuel range shown is 330 mi (at 30 mpg average gas mileage) when it should be closer to 500 mi with specified fuel tank capacity of 17 gal and 30 mpg. Shortly after filling the fuel tank, the fuel gauge and range will quickly decrease while driving. From researching and reading dozens of online forums about this issue, I tested filling the tank manually at the pump, extremely slowly, not using the auto fill lever. Two times doing this test, I was able to pump 14.5 gal into the tank before the pump kicked off. After these fill ups, the fuel gauge showed full and did not quickly decrease when driving. Also, the range now showed 450+ mi remaining. Both times after what appears to be an actual full tank fill up, the vehicle recorded over 400 miles before the fuel low light turned on, while previous max miles was in 300 range. It seems as if the fuel tank design ds not allow the fuel to enter and settle in the tank quickly enough when filling, causing the pump to kick off prematurely and not actually fill up the tank. This issue causes the vehicle to not reach the full mileage range with advertised MPG and tank capacity, causing more frequent and inconvenient trips to the gas station. We have taken the vehicle to a Toyota Service center and they documented the issue but were told by Toyota Corporate that they do not have a fix for it at this time. Tech Tip T-TT-0742-23 exists on NHTSA.GOV website related to this issue from November 2023.