When a user tags someone from the web or from a device, the notification that is generated is incorrect. Object_type and Object_id is blank. Issue also exists on the iPhone.

API Call:
facebook.stream.publish
FQL multiquery

Competitor Platform:
iPhone ALSO faces the same issue and is reproducable. Use the + symbol on the web to tag a friend. Observe that friend does not receive a notification on the iPhone, but they do receive one on the web.

Web console check:
Same behavior using FQL query to pull notifications using graph explorer

Request/Response:
--Part-Boundary
Content-Disposition: form-data;name="format"

JSON
--Part-Boundary
Content-Disposition: form-data;name="message"

3 people tagged in this post
--Part-Boundary
Content-Disposition: form-data;name="method"

facebook.stream.publish
--Part-Boundary
Content-Disposition: form-data;name="privacy"

{"value":"EVERYONE"}
--Part-Boundary

Content-Disposition: form-data;name="tags"
[100002559070595,100002935359087,100002409933110]
--Part-Boundary

The resulting post generated from the request:
"fql_result_set": [
{
"post_id": "100002400272988_283598865063454",
"viewer_id": 100002400272988,
"app_id": 2254487659,
"source_id": 100002400272988,
"updated_time": 1335811087,
"created_time": 1335811087,
"attribution": "BlackBerry",
"actor_id": 100002400272988,
"target_id": null,
"message": "3 people tagged in this post",
"description": null,
"app_data": [],
"action_links": null,
"comments": {
"can_remove": true,
"can_post": true,
"count": 0,
"comment_list": []
},
"likes": {
"href": "http://www.facebook.com/browse/likes/?id=283598865063454",
"count": 0,
"sample": [],
"friends": [],
"user_likes": false,
"can_like": true
},
"privacy": {
"description": "Public",
"value": "EVERYONE",
"friends": "",
"networks": "",
"allow": "",
"deny": ""
},
"filter_key": "nf",
"permalink": "http://www.facebook.com/permalink.php?story_fbid=283598865063454&id=100002400272988",
"tagged_ids": [
100002409933110,
100002935359087,
100002559070595
],
"impressions": null,
"description_tags": [],
"message_tags": [],
"attachment": {
"description": ""
},
"place": null,
"with_tags": [
100002409933110,
100002935359087,
100002559070595
]
},

Run query using account and user id of the person that was tagged to retrieve their notification:

"SELECT notification_id,app_id,sender_id,created_time,updated_time,title_text,body_text,object_id,object_type,is_unread,is_hidden FROM notification WHERE recipient_id=100002409933110"

Response:
[
{
"name": "notifications",
"fql_result_set": [
{
"notification_id": "9881026",
"app_id": 2719290516,
"sender_id": 100002400272988,
"created_time": 1335811088,
"updated_time": 1335811088,
"title_text": "Trenton Rufus said he was with you and 2 others in a status update.",
"body_text": "",
"object_id": "",
"object_type": "",
"is_unread": 1,
"is_hidden": 0
}
]
},

Observe the object_id and object_type is blank. Object_type should be of type 'stream' and object ID should be the post_id