hello, installed 12 beta 1 in my orange pi3 lts (SD card install to keep my emmc installation and settings), this i have found:
-first boot after installing its ok, but after doing some config (country, language, time zone and others including static ethernet IP to have access with Kore app), second reboot (always with power off-on cycle), then ethernet connection is not working anymore, no ethernet detected after several reboots (this issue happends to me with Nexus 11.0.x sometimes as well, but not often and after one reboot the ethernet conn works again normally).
-2nd format SD and reinstall, ethernet detected, no personal config done, reboot and no ethernet, 2nd boot no ehernet, 3rd reboot ethernet working, again testing to disable dhcp and set static IP (thinking this may be the problem) and again no ethernet anymore after reboot, but...
-third SD fresh install, first boot no ethernet (just after SD rearrange by Libreleec), no config changes made, second reboot ethernet working... after that i tried severals (20-25 times) shutdown+power off-on cycle with more than 90% no-ethernet issue after a new reboot, seems to be random fails but quite more often than with 11.0.x.
cheers