diff --git a/api/assign_device.go b/api/assign_device.go
index 3d6676b..5a7a583 100644
--- a/api/assign_device.go
+++ b/api/assign_device.go
@@ -161,7 +161,7 @@ func (handler *AssignDevice) PutAssignDeviceToHomeRoom(c *gin.Context) {
 			return nil, errClean
 		}
 
-		// 5. assign device with id = `deviceID` to room with id = `assignDeviceReq.RoomID` of home with id = `assignDeviceReq.HomeID`
+		// 5. assign device with id = `deviceID` to room with id = `roomObjID` of home with id = `homeObjID`
 		filterHome := bson.D{bson.E{Key: "_id", Value: homeObjID}}
 		arrayFiltersRoom := options.ArrayFilters{Filters: bson.A{bson.M{"x._id": roomObjID}}}
 		opts := options.UpdateOptions{
@@ -173,8 +173,8 @@ func (handler *AssignDevice) PutAssignDeviceToHomeRoom(c *gin.Context) {
 			},
 			"$set": bson.M{
 				"rooms.$[x].modifiedAt": time.Now(),
+				"modifiedAt":            time.Now(),
 			},
-			// TODO I should update `modifiedAt` of both `home` and `room` documents
 		}
 		_, errUpdate := handler.collHomes.UpdateOne(sessionCtx, filterHome, update, &opts)
 		if errUpdate != nil {
diff --git a/api/register.go b/api/register.go
index 9b55f89..dfe1324 100644
--- a/api/register.go
+++ b/api/register.go
@@ -344,7 +344,7 @@ func (handler *Register) insertDevice(device *models.Device, profile *models.Pro
 		_, errUpd := handler.collProfiles.UpdateOne(
 			sessionCtx,
 			bson.M{"_id": profile.ID},
-			bson.M{"$push": bson.M{"devices": device.ID}},
+			bson.M{"$addToSet": bson.M{"devices": device.ID}},
 		)
 		if errUpd != nil {
 			return nil, customerrors.Wrap(http.StatusInternalServerError, errUpd, "Cannot update profile with the new device")
diff --git a/testuutils/db_utils.go b/testuutils/db_utils.go
index ac18b80..10ec93f 100644
--- a/testuutils/db_utils.go
+++ b/testuutils/db_utils.go
@@ -90,7 +90,6 @@ func AssignDeviceToHomeAndRoom(ctx context.Context, collectionHomes *mongo.Colle
 		"$set": bson.M{
 			"rooms.$[x].modifiedAt": time.Now(),
 		},
-		// TODO I should update `modifiedAt` of both `home` and `room` documents
 	}
 	_, err = collectionHomes.UpdateOne(ctx, filterHome, update, &opts)
 	return err