Installed appx fails code integrity policy - windows

Question

I'm developing an Electron app and the current build is ready to be rolled out. I have enabled the audit mode on a virtual machine.
This is the error I am getting in the Event viewer:
Code Integrity determined that a process (<path_to_system32>\svchost.exe) attempted to load <path_to_app>\my_app.exe that did not meet the Custom 1 signing level requirements or violated code integrity policy (Policy ID:{a244370e-44c9-4c06-b551-f6016e563076}). However, due to code integrity auditing policy, the image was allowed to load.
I've installed this app with his .appx. Get-AuthenticodeSignature says that my signed appx is valid.
If I run my Get-AuthenticodeSignature in the installed folder, my exe is not signed, the dlls however are correctly signed.
My second error messages looks a little bit different:
Code Integrity determined that a process (<path_to_app>\my_app.exe) attempted to load <path_to_app>\<some_dll>.dll that did not meet the Custom 1 signing level requirements or violated code integrity policy (Policy ID:{a244370e-44c9-4c06-b551-f6016e563076}). However, due to code integrity auditing policy, the image was allowed to load.
The <some_dll> are ffmpeg.dll, d3dcomiler_47.dll, swiftshader/libGLESv2.dll and swiftshader/libEGL.dll.
my package.json looks like this:
"appx": {
"identityName": "company.myapp",
"backgroundColor": "#FFFFFF",
"publisher": "CN=company, O=company, STREET=xxxx, L=yyyy, S=zzzz, PostalCode=1234, C=xx",
"publisherDisplayName": "company",
"displayName": "myapp",
"languages": [
"nl",
"en",
"fr"
]
},
"win": {
"target": "nsis",
"icon": "icons/icon.ico",
"publisherName": "Company",
"certificateFile": "./certs/certificate.p12",
"certificatePassword": "mypassword",
"certificateSubjectName": "company",
"signAndEditExecutable": true,
"signDlls": "true",
"sign": "./customSign.js",
"extraResources": [
"electron/bin/*.exe"
],
"verifyUpdateCodeSignature": true
}