Asus RTX3080 TUF OC is rated for 370W power limit. However, even with latest BIOS and powerlimit set to max, it only draws 350W of power. Can this be fixed with a software update or is it a hardware issue?

The power limit prevents the GPU to reach higher clocks. Some other 2x8pin 3080 cards successfully draw more power so that shouldn't be the cause for the issue.