Single Fiddle Main Halyard Block

At the end of my first season with Romilly no.16, seasons end being in October 2015 when the mast came out and I could see the block up close, I discovered that part of the cheek of the Lewmar Single Fiddle block (see photo) my boat uses for the main halyard was broken off. This was the reason why the halyard was jamming and jumping off the sheave.

I am told the block is less than three years old.

I wonder if during a gybe the block became squashed between mast and gaff. Perhaps it couldn’t swivel freely quickly enough; perhaps the halyard had developed twist in it.

Has anyone had a similar issue with their main halyard block?

Nigel Manning