Information messages displayed using "addInfoMessage" from a script include showing multiple times at the top of a form

Using an addInfoMessage to show an information message at the top of the form, shows up multiple times

1. Create a Script Include
   • Name: jjTest
   • Check "Client Callable"
   • Script:

     var jjTest = Class.create();
     jjTest.prototype = Object.extendsObject(AbstractAjaxProcessor, {
       popUpInfo: function(current){
         gs.addInfoMessage("This is just a test. Carry on!") },
         type: 'jjTest'
       }
     );

   • Save
2. Create a UI Action
   • Name: JJ Popup
   • Table: sys_update_set
   • Action name: jj_pop_up
   • Check booleans:
     • Show Update
     • Client
     • List v2 Compatible
     • Form Button
   • Onclick: run()
   • Condition: new jjTest().popUpInfo(current)
   • Script: new jjTest().popUpInfo();
   • Save
3. Go to sys_update_set.list
4. Open an existing record
5. You will notice 2 or more pop-ups at the top of the screen

Expected behavior: Only one message should show up on at the top of the screen

Actual behavior: Having multiple messages show up at the top of the screen

This is expected behavior and by design in all currently supported releases.

Recommendation: never add messages during a server-side script call that is being used in a condition. This an anti-pattern and not recommended. Condition processing should only be used to evaluate a final answer of true or false and nothing more.