Rule fired when "User votes on a Node" is being fired even if the user is not allow to vote?

I have some problem with a rule which is fire when User votes on a Node.

I'll try to recreate the situation:

I create a widget of the type: Number up / down widget
I enabled the widget for the node type Answer

Then the user is able to vote up or down an Answer. So far so good

I create a rule which is fire when User votes on a Node
I added the condition "Check the value of the vote" is "1"

Now the user "vote up" an answer one time: the vote is added and the rule is fired (this is all right)

Problem:
Then, the same user "vote up" the same answer. the vote is not added (this is right) but the the rule is fired (this is wrong). The rule must be fire only if the node get the vote.

How can fix this? Do I need to add another condition to the rule?