If you didn't hit something or sailed in a storm when this happened, it is most likely due to the new rigging tension. If you are confident about your rigging tune job, that I think you should glass get rid of this spray tabbing and use fiberglass and do that for every other place this was used. Factory choices are not always the best ones. Just my opinion as I said I am not familiar with this material. Brittle structural members have no place on a boat.
1978 Gulfstar 50'
Clark Sailing Dinghy 10'