diff --git a/taiga/base/utils/db.py b/taiga/base/utils/db.py
index 3ef8ba6e..f1d59adb 100644
--- a/taiga/base/utils/db.py
+++ b/taiga/base/utils/db.py
@@ -62,7 +62,7 @@ def save_in_bulk(instances, callback=None, precall=None, **save_options):
 
         precall(instance)
         instance.save(**save_options)
-        callback(instance, created=True)
+        callback(instance)
 
 
 @transaction.atomic
diff --git a/taiga/projects/api.py b/taiga/projects/api.py
index 9b623739..07a5bb7c 100644
--- a/taiga/projects/api.py
+++ b/taiga/projects/api.py
@@ -205,6 +205,15 @@ class MembershipViewSet(ModelCrudViewSet):
         services.send_invitation(invitation=invitation)
         return Response(status=status.HTTP_204_NO_CONTENT)
 
+    def pre_save(self, object):
+        # Only assign new token if a current token value is empty.
+        if not object.token:
+            object.token = str(uuid.uuid1())
+
+        object.user = services.find_invited_user(object, default=object.user)
+
+        super().pre_save(object)
+
     def post_save(self, object, created=False):
         super().post_save(object, created=created)
 
diff --git a/taiga/projects/models.py b/taiga/projects/models.py
index 317ef5e2..6f943491 100644
--- a/taiga/projects/models.py
+++ b/taiga/projects/models.py
@@ -15,7 +15,6 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import itertools
-import uuid
 
 from django.core.exceptions import ValidationError
 from django.db import models
@@ -32,7 +31,7 @@ from djorm_pgarray.fields import TextArrayField
 from taiga.permissions.permissions import ANON_PERMISSIONS, USER_PERMISSIONS
 
 from taiga.base.tags import TaggedMixin
-from taiga.users.models import User, Role
+from taiga.users.models import Role
 from taiga.base.utils.slug import slugify_uniquely
 from taiga.base.utils.dicts import dict_sum
 from taiga.base.utils.sequence import arithmetic_progression
@@ -74,14 +73,6 @@ class Membership(models.Model):
         if self.user and memberships.count() > 0 and memberships[0].id != self.id:
             raise ValidationError(_('The user is already member of the project'))
 
-    def save(self, *args, **kwargs):
-        if not self.token:
-            self.token = str(uuid.uuid1())
-
-        self.user = User.objects.filter(email=self.email).first()
-
-        super().save(*args, **kwargs)
-
     class Meta:
         verbose_name = "membership"
         verbose_name_plural = "membershipss"
diff --git a/taiga/projects/services/__init__.py b/taiga/projects/services/__init__.py
index 54a9a343..cd394f9a 100644
--- a/taiga/projects/services/__init__.py
+++ b/taiga/projects/services/__init__.py
@@ -35,5 +35,6 @@ from .members import create_members_in_bulk
 from .members import get_members_from_bulk
 
 from .invitations import send_invitation
+from .invitations import find_invited_user
 
 from .tags_colors import update_project_tags_colors_handler
diff --git a/taiga/projects/services/invitations.py b/taiga/projects/services/invitations.py
index c9531eb7..13ca2743 100644
--- a/taiga/projects/services/invitations.py
+++ b/taiga/projects/services/invitations.py
@@ -10,3 +10,17 @@ def send_invitation(invitation):
         template = mbuilder.membership_invitation
     email = template(invitation.email, {"membership": invitation})
     email.send()
+
+
+def find_invited_user(invitation, default=None):
+    """Check if the invited user is already a registered.
+
+    :param invitation: Invitation object.
+    :param default: Default object to return if user is not found.
+
+    :return: The user if it's found, othwerwise return `default`.
+    """
+    try:
+        return type(invitation).user.get_queryset().filter(email=invitation.email).all()[0]
+    except IndexError:
+        return default