Having looked in my spares box I have 3 broken long tang guards that I have removed from scrap / to be restored rifles.
It isn’t possible to say where they broke as they have been tidied up, but 2 have half the tang left and have been drilled in the past to make a new scoring screw hole.

The other has had the whole tang removed bar maybe a quarter of its original length and again a new screw hole drilled through it.

I assume bsa either found the original version had too much wastage in manufacture, or it saved money in the stock work in changing the design.