I lay odds that toggle was already cracked. I've had them crack on other boats (always caught it during inspection) and I've seen them crack on other's boats. They seem unusually vulnerable to fatigue.
https://www.practical-sailor.com/blog/Whats-Hiding-in-Your-Rig-11675-1.html
https://www.practical-sailor.com/blog/Whats-Hiding-in-Your-Rig-11675-1.html