In my builds I am using drivers from main LibreELEC tree and they are also included in RPi builds. Can you post dmesg, lsmod and lsusb -v so that developers can see what is wrong?
Here are the results: # dmsg: line 5 # lsmod: line 633 # lsusb -v: line 643 yianniBox:~ # dmsg - Pastebin.com
Note: To connect to the LAN, I used a RTL8188CUS WLAN USB Adapter in addition to the Edimax AC600.
More over, the Edimax AC600 has troubles searching for ESSIDs.