GuideDropDownList resetData() does not work

I created a test with a textbox, a dropdown list (multiselect), and button

the textbox resets the dropdown list when you change the value of the textbox.

the button is just a click event that is there for pretending i am doing something with the textbox value. it actually just writes to the console.

so i write something on the textbox and click the button, this should reset the values of the dropdown. then I choose one item

then i do it again i write "test again" and click the button, this clears the items from the dropdown list

then i click on "4" item of the drop down list and the value "2" comes back. 

but ddlist.resetData() was supposed to reset the data of the dropdown and "2 was not supposed to be highlighted. this is happening in AEM forms 6.5 SP19. can you please try in other services packs? or did i miss something ? 

thanks in advance.