We know that Hydaelyn sundered Zodiark, but was she herself sundered in the process? If she is not and/or became the will of the planet her "distress beacon"/or saying "Hear, Feel Think" is just something all can hear since she became the will in essence.
Another thought is again, speculation. As we got closer to being close to our original self (as we besides the Ascians) have the most complete version it may be possible the less "in tune" we are with her - where others may see it as a distress beacon of the planet we call Hydaelyn.
The distress signal may have been always there so that darkness could not be defeated so soundly and at least had a means to be held in check.