I'm confused about how to close the inventory screen. While viewing the inventory, about 3% of the time, pressing Esc closes the inventory; but the vast majority of the time, pressing Esc displays the "Press Esc again to exit to title" instead (and then of course, pressing it a 2nd time kicks me to the main menu). I have no idea what I'm doing differently that 3% of the time.

You have to press the "Menu" key, which by default is mapped to S. Works for me.

Oh, that explains it. It looks like I had remapped "menu" to the Esc key (and then later assumed that was the default mapping so I didn't try changing it).

Thanks for your help.

I did the same thing. and have been searching the internet forever trying to figure it out.
thank you!