I just started playing with 2016 SP3.
I have "Always PXE BOOT UEFI Devices" checked in Pxe Boot Options. These are the things I've tried. Note: the device is not in Landesk database.
1. Booted the computer up, it went to windows screen.
2. Booted to F12 and selected UEFI IPV4, went to black screen waiting for PXE.
3. Added the computer as bare metal. Drug it to a scheduled task, Booted to F12 selected UEFI IPV4, started task, went to black screen waiting for PXE.
Legacy (non-UEFI) devices work ok. The manual states Always PXE Boot UEFI Devices allows you to PXE boot without Pre-Scheduling a task. What does that mean?