Since this problem is exists on our server very long, and someone bumped the topic, i decided to reproduce the skill delay bug, after 5 tries we succeded. Here is the video of getting debuff on Brilliant Purge:
Brilliant Purge -> Immunity + Removing all debuff. So in what way server is processing the skills, cause there is no way to have debuff on Brilliant Purge (should be no way) since when its activated removing all debuff and giving 7 second immunity.
Thank you for submitting a request to Support Service and for additional info provided. Video along with other materials will be sent to developers.