File.readAsText never resolves

Ionic Framework ionic-v3
24

Hello, I got this issue sometimes, not always and I can’t figure why yet.
We use FileTransfer, Zip and File from Ionic native.
My code looks like this:

const fileTransfer: FileTransferObject = self.transfer.create();
fileTransfer.download(url, file.dataDirectory + FILE_NAME)
	.then(() => {

		self.zip.unzip(file.dataDirectory + FILE_NAME, file.dataDirectory)
			.then((result) => {

			if (result == 0) {
					
					// Always get here but sometimes, readAsText never resolves...
					
					file.readAsText(this.file.dataDirectory, NOM_FICHIER_XML)
						.then((data) => {
							
						})
						.catch((Error) => {
							
						})
			}
		}
	}

ionic info:

cli packages: 

    @ionic/cli-utils  : 1.13.0
    ionic (Ionic CLI) : 3.13.0

global packages:

    cordova (Cordova CLI) : 7.1.0

local packages:

    @ionic/app-scripts : 3.0.0
    Cordova Platforms  : android 6.3.0
    Ionic Framework    : ionic-angular 3.7.1

System:

    Android SDK Tools : 26.0.1
    Node              : v6.9.5
    npm               : 4.2.0
    OS                : Windows 7

Config.xml:

<plugin name="cordova-plugin-file" spec="4.3.3" />
<plugin name="cordova-plugin-zip" spec="3.1.0" />
<plugin name="cordova-plugin-file-transfer" spec="1.6.3" />

Package.json:

"@ionic-native/file": "4.3.1",
"@ionic-native/file-transfer": "4.3.1",
"@ionic-native/zip": "4.3.1",

The workaround about placing cordova.js after polyfills.js works for us, but it kind of break the splash screen (where the splash screen is rapidly replaced with a gray background at startup).

Any idea why the File.readAsText() doesn’t resolve sometimes ?

Thanks.