How to prevent recursion when setting a data value for a user in rules?
Your question seems like a variation of the question 'Why is my rule that reacts on event &quot;After updating an existing user account&quot; firing twice?'. The accepted answer in that question might help to understand your issue (what's causing it) also, ie:


  some other module code is calling a user_save on hook_user_update triggering the rules event a second time.


That question also has another answer with a very interesting workaround, with an image which looks like so (a picture is worth more then 1000 words):