Modifying django-allauth error messages on a signup form

Question

I'm currently building a website that makes use of django-allauth and I've come across a problem regarding error messages while using a custom User model.

My custom User model is called CustomUser, I've noticed that when django-allauth handles errors regarding the username, it uses the name of the user model as the starting word to the error message's sentence. Example image is linked below.

Image of the error message

How can I change this error message? I'd like to stay away from overriding any django-allauth views if possible, though I'd be happy with any solution!

This is my Django form code that makes use of django-crispy-forms:

        <form class="signup" id="signup_form" method="post" action="{% url 'account_signup' %}">
          {% csrf_token %}
          <div class="row">
            <div class="col-12 col-lg-7">
              {{ form.email|attr:"autofocus"|as_crispy_field }}
            </div>
            <div class="col-12 col-lg-5">
              {{ form.username|as_crispy_field }}
            </div>
            <div class="col-6 col-lg-4">
              {{ form.first_name|as_crispy_field }}
            </div>
            <div class="col-6 col-lg-4">
              {{ form.last_name|as_crispy_field }}
            </div>
            <div class="col-12 col-lg-4">
              {{ form.birthday|as_crispy_field }}
            </div>
            <div class="col-12 col-sm-6">
              {{ form.password1|as_crispy_field }}
            </div>
            <div class="col-12 col-sm-6">
              {{ form.password2|as_crispy_field }}
            </div>
            <div class="col-12 text-center">
              {{ form.captcha|as_crispy_field }}
                {% for error in form.captcha.errors %}
                  {% if error %}
                  <style>
                    #div_id_captcha {
                      margin-bottom: 0px !important;
                    }
                  </style>
                  <span class="invalid-feedback d-block mb-3">
                    <strong>
                      You must complete the captcha to register
                    </strong>
                  </span>
                  {% endif %}
                {% endfor %}
            </div>
          </div>
          {% if redirect_field_value %}
          <input type="hidden" name="{{ redirect_field_name }}" value="{{ redirect_field_value }}" />
          {% endif %}
          <button type="submit" class="btn btn-primary btn-light mb-3">Register <i class="fa fa-user-plus fa-fw"></i></button>

          <p>Already have an account?<br /><small><a href="{{ login_url }}">Login here</a></small></p>
        </form>