It would be great if someone from Dell could acknowledge this as a bug report, as at least a few other users have had this problem. See this link for the previous discussion:
EXPECTED BEHAVIOR: When my XPS 10 is attached to its keyboard dock and I close it to put the system to sleep/suspend, the system should stay in a low-power state until the next time it is opened.
ACTUAL BEHAVIOR: When closed, the system will initially stay asleep for anywhere from a few seconds to a few minutes, but without fail, it will eventually wake and stay not only running, but running with the screen on until the system is opened again or until the battery is depleted.
STEPS TAKEN TO RESOLVE PROBLEM: 1) Factory reset. No effect. 2) Windows RT 8.1 preview installation. No effect. 3) Using Dell Dock Settings app, disable trackpad. System will now sleep while dock is attached for a few minutes to an hour, at which point a Windows RT crash causes the machine to reboot and stay awake until the system is opened or the battery is depleted.
ADDITIONAL INFORMATION: Taking the system off the dock and placing a small magnet over the sensor on the tablet that determines whether or not the system is closed will cause it to sleep until woken by removing the magnet. Additionally, removing the tablet from the dock and placing it lined up where it would be if it were attached and closed will cause the tablet to sleep until moved off the dock again.
If this is not an appropriate place to seek assistance from Dell on this matter, does anyone have a direct contact or bug report address to which I can send this?
I just located yet another thread that went without an official response. It is located here:
Please note one user there confirms my step 3 above, that user input is the problem. When closed, the system should power down or at least ignore any input from the keyboard or trackpad. It apparently does not, based on the kernel power events that user jayflowk located in system logs.