Chance to Ignore Stuns when Casting not Working Properly.

Hi. I am noticing that when I reach 100% chance to ignore stuns when casting, the effect of STUN does not happen at all in my character. This is an incorrect interaction, the status of STUN should happen in my character (including all the upsides with masteries) but I should be able to continue casting (ex: channeling) If this was not the intended interaction, then the text should say % Chance to avoid being stunned, as for example the notable Perfectionist.