Why is my bottom navigation assuming my activity height instead of my FragmentContainerView's?

My bottom navigation fragments are assuming my activity height instead of my FragmentContainerView's. I would like to know what the cause might be.

This is my bottomNavigation activity:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/default_background"
    tools:context=".ui.MainActivity">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/fragment_container_tab"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@+id/bottomNavigationView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:layout="@layout/fragment_blank" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottomNavigationView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/nav_menu" />

</androidx.constraintlayout.widget.ConstraintLayout>

My interface is looking something like this, in this particularly case I have a marginBottom of 32dp, but as you can see the view is assuming my activity constraints.

(I'm sorry before I forgot the print)

I expect the result to be something like this, that is my preview screen. I want the bottom of my fragment to be the top of the BottomNavigationView:

I don't know what code can help finding the solution for this issue but I can provide more code if needed

I had two different activity_main files, and one of the files had a small bug in the XML. I don't know how that second activity was created in the first place.