Problem with summarize

Hi,

I need some help with the summarize function. I cannot somehow find out how to do it:

What I've done so far:

added a new heartbeat message for adding forum topics...:

Unique but descriptive message id: "user_add_forum_topic"
Description of the message: "User adds a Forum topic, save user activity"
Message display access: "Everyone can see this message"
Single message: "!username has added forum topic !node_title"
Type of message: "summary"
Message to group instances: "!username has added forum topics %node_title%"
Group by: "Group by users to summarize nodes"
Variable to summarize: "node_title"
Maximum number of messages to group: "5"
Fill in the target separator: ", "
Fill in the target end separator.: " and "

In Rules then I've created a rule for adding forum topics:

Label: "User add new forum topic"
Event: "After saving new content"
Conditions: "Published" AND "type is Forum topic"
ACTION:
Label: "Logs user activity for single users"
User: "[user:user-id]"
User target: "0"
Node context: EMPTY
Node target: "[node:nid]"
Choose a message: "User adds a Forum topic, save user activity"
Assign a token to each of these variables used in the selected message:
"@username=[user:user-name-url]
@node_title=[node:title-link]
@club=[node:ogname-title-link]"

This is pretty much the same as if you add a new node, only changed to forum topic.

When adding two or more forum topics, they are still handled as single messages on separate rows. I'm using the "heartbeat_activity_personal" view to show the messages in a panel on the user profile page and they are showing but one by one. What am I missing, (apart from Heartbeat basis knowledge :( )

Thanks for any help!