i have same "problem", but I'm lucky because i dont want to use rx 580... So same rig with amd and nvidia, and it only detects nvidia..
--list-devices do not work. It keeps runing command prompt again and again, over and over (shut down then start, shut down then start). but miner works fine, when start mining and only detecting nvidia..

--platform , --device , --list-devices
OpenCL is organized in platforms, that correspond to the driver to be used for the Miner. On many system –
in particular when the CPU features an integrated graphic card – there is more then one platform on the
system available.

The parameter platform can be used to select the right platform. lolMiner offers the option --list-devices.
When lolMiner is started with this parameter it will print out a list with all platforms that were found on the
system. Additionally for every platform all devices are printed that are found within a platform.
After printing out the miner will close directly. To see the output in Windows you must run cmd (the
Windows command line), navigate to the directory where lolMiner-mnx.exe is in and then run lolMiner-
mnx.exe --list-devices directly from the command line. Writing the --list-devices to the configuration file is
not supported and running in the batch will end up in the miner closing instantaneously and you do not see a
print out.

From lolMiner-mnx 0.3 there is one special value AUTO that can be passed to the miner and also is the
default. This one will select the platform with the most graphic cards automatically. If there are two with the
same number, e.g. and Intel integrated GPU and one AMD / Nvidia graphic card it will prefer the non-Intel
platform.

P.S. I hope the stability of Windows improves...