To reproduce:
1) Open up the attached project
2) Build the "Main" scene with "Development build" option checked on a Windows standalone version
3) Create .bat file with following lines:
start BUILTFILENAME.exe -force-opengl -screen-width 640 -screen-height 480
exit
4) Launch .bat file and you will see an error message "AssetBundle.Unload(false) shouldn't be called because assets might have to be reloaded at any point in time. If no assets are used, call AssetBundle.Unload(true)" . The error message doesn't appear if launched normally(when not forcing OpenGL)

Edit: The reason we cannot call AssetBundle.Unload(false) is we need the resources can be read from assetbundle again for some cases like alt tab on windows phone, changing resolution on opengl."