Not showing learning suggestion for illegal parameter

In our application we had a URL "/bc/login" for which default json profile was applied. In default json profile parse parameter option was not enabled. As a result f5 was not able to see parameters in that URL. Now we have created a new json profile in which parse parameter option is enabled and now we tagged that json profile to "/bc/login" URL. Now I am seeing requests are blocking as "illegal parameter" violation is triggered and in event log I am also seeing those illegal parameters. But in those blocked requests there is no suggestion to accept those illegal parameter though I am using automatic learning. So I have added those parameters manually in that URL. But I want to learn those parameters automatically. So what is the reason for not providing any learning suggestion?