damaged fiber pin

i was checking fiber harness and power loss was in one direction -14.75db and in other direction -1.60db. looking in back of one of the connectors i noticed light coming out of the pin, others did not have it. i did not have a chance yet to remove it but i was wondering what can it be caused by; is it crashed fiber or damage done during installation, or is it something that maybe able to repair.

other wires (not all but some) were checked and look good..., wire to pin that has that "glow" is not tight and there is small slack (as should be), pin wont go in or come out.
i think this happened during installation and probably it got pushed too hard and got cracked or was nor crimped properly in the beginning.
i have not seen such issues before (yet) and was wondering if anyone associated this to some known defect.