Having trouble in loading audio file resources from RCP bundle.

RealityContentKit bundle resource issue

Recently I always encounter weird loading bugs from RealityKitContent bundle. When I was trying to load audio resource as AudioFileResource or AudioFileGroupResource by loading from *.usda from RealityKitContent bundle, with this method. My code is nothing complicated but simple as below:

let primPath: String = "/SampleAudios/SE_bounce_audio"
guard let resource = try? AudioFileGroupResource.load(named: primPath, from: "MyScene.usda", in: realityKitContentBundle) else {
       return
}

And the runtime program "sometimes"(whenever I change something RCP it somethings work again but the behavior is unpredictable) reports that it "Cannot find MyScene.usda:/SampleAudios/SE_bounce_audio in RealityKitContent.bundle".

I put MyScene.usda under the root folder of RealityKitContent package because I found that RealityKit just cannot find any *.usda scene if you didn't put that on the root level (could be a bug because of the way it indexes its files).

I even double checked my .usda file with usdview, the primPath is absolutely correct. I think there are some unknown issues when RealityKitContent copy resources and build the package. I tried to play with the package Package.swift file a bit to see if I could manually copy my resources (everything) and let the package carry my resources but it just didn't work. So right now I just keep this file untouched below (just upgrade the swift-tools-version to 6.0 as only that can supports .visionOS(.v2)):

// swift-tools-version:6.0
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "RealityKitContent",
	platforms: [
		.visionOS(.v2)
	],
    products: [
        // Products define the executables and libraries a package produces, and make them visible to other packages.
        .library(
            name: "RealityKitContent",
            targets: ["RealityKitContent"]),
    ],
    dependencies: [
        // Dependencies declare other packages that this package depends on.
        // .package(url: /* package url */, from: "1.0.0"),
    ],
    targets: [
        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
        // Targets can depend on other targets in this package, and on products in packages this package depends on.
        .target(
            name: "RealityKitContent"
        ),
    ]
)

That is just issue one, RealityKitContent package build issue.

Audio file format issue

Another is about Audio File Format RCP supports. I remember is a place (WWDC?) saying .wav and .mp4 are supported to be used as audio source. But when I try to set up Spatial Audio, I find sometimes *.wav or *.mp3 can also be imported as AudioSourceFile. But the behavior is unpredictable. With two *.wav files SE_ball_hit_01.wav and SE_ball_hit_02.wav, only SE_ball_hit_01.wav is supported, 02 is reported as the format is not supported/ Check out my screenshots to see the details of two files. Two files have almost the same format (same sample rate or channel).

I understand there might be different requirements for a source file to be used as Spatial or Ambient audio. But I haven't figured that out or there is nothing I can find helpful on Apple Documentation. So what is the rules?

Thanks for reading and any thought is welcomed.