Why file being created in electron-builder install process is being removed from the installation user folder?

Question

While adding a script to run in the process of installation, I see the file I'm writing into being deleted or removed from the installation directory. Why?

my vue.config.js file:

pluginOptions: {
    electronBuilder: {
      builderOptions: {
        appId: 'test.com',
        win: {
          "target": ["nsis"] 
        },
        "nsis": {
          "include": "build/installer.nsh",
          "oneClick": false,
          "allowToChangeInstallationDirectory": true
        }

      }
    }
  }

my script create new file and write inside user name/password:

my installer.nsh file:

!include nsDialogs.nsh
!include LogicLib.nsh

XPStyle on

Var Dialog
Var UserLabel
Var UserText
Var UserState
Var PassLabel
Var PassText
Var PassState

Page custom nsDialogsPage nsDialogsPageLeave

Function nsDialogsPage

    nsDialogs::Create 1018
    Pop $Dialog

    ${If} $Dialog == error
        Abort
    ${EndIf}

    ${NSD_CreateLabel} 0 0 100% 12u "Your Username:"
    Pop $UserLabel

    ${NSD_CreateText} 0 13u 100% 12u $UserState
    Pop $UserText

    ${NSD_CreateLabel} 0 39u 100% 12u "Your Password:"
    Pop $PassLabel

    ${NSD_CreatePassword} 0 52u 100% 12u $PassState
    Pop $PassText

    nsDialogs::Show

FunctionEnd

Function nsDialogsPageLeave

    ${NSD_GetText} $UserText $UserState
    ${NSD_GetText} $PassText $PassState

    ${If} $UserState == ""
        MessageBox MB_OK "Username is missing."
        Abort
    ${EndIf}

    ${If} $PassState == ""
        MessageBox MB_OK "Password is missing."
        Abort
    ${EndIf}

    StrCpy $1 $UserState
    StrCpy $2 $PassState

FunctionEnd

Section

  SetOutPath "$INSTDIR\myfolder" 
  FileOpen $9 $INSTDIR\myfolder\credentials.txt w
  FileWrite $9 "$1 $2"
  FileClose $9
 

SectionEnd

While running the setup.exe file I can see it creates "myfolder" and also creates the "credentials.txt" file and update it, but when the process ends - the folder stays empty. The file was removed. Why? What I'm missing here?