If you have the keyboard plugged in the proximity sensor is deactivated (confirmed this with Tech Support), this is just silly. So you are forced to hit a key to get the backlight to come back on...
I have my MX Keys S keyboard backlight time set to 30 minutes (the longest time currently allowed), but it will turn off whenever if feels like.
I also have a K800, with that keyboard you can set the backlight to be always on, that is nice...
So many people have asked for this keyboard backlight to have better options, like "Leave Backlight ON"... If there's a big worry about the battery life, what about the option of: "Leave Backlight ON while plugged in", that would work just fine...
Please, please...

Perhaps also an adjustment on the sensitivity for coming on. I'm finding my keyboard backlight is constantly going on and off while using my desk with the keyboard pushed to the back (not touching it). Somehow it's detecting me or my movement or whatever, and the backlight coming on randomly, then back off after a few seconds is quite distracting.

Also please add an option to disable the: Backlighting Bright Environment Issue, I would like to have the option to turn on backlighting even if I am in a bright environment