load asset async from dlc pak file failed

Development Programming & Scripting C++
1

I use Projectlauncher make a release version and make a dlc pak file based on this release version.
in the game i mount dlc pak file and load asset in dlc，but it notice the file contains unrecognizable data, check that it is of the expected type.

log file, source code, Projectlauncher configs is in Attachments.
log file: LoadTest.log.txt(file extension name is modified for uploading)
Projectlauncher config for release:release_config.jpg
Projectlauncher config for dlc:dlc_config.jpg

I use RunLoad function of class AImportPakFile to load asset from dlc pak file.
I tried both WindowsNoEditor and Android_ASTC platfroms and both failed for the same reason.
My Unreal version is 4.11.2

2

UE4 find and analysis all *.pak files when it init(FEngineLoop::PreInit)
use below paths:
[Demo]/Content/Paks/
[Demo]/Saved/Paks/
Engine/Content/Paks/
check func :FPakPlatformFile::FindFileInPakFiles() ,you can get somethings maybe