........and discovered my 'magic link' was not
so magic, but had decided to crack in half. I had been using the
assymmetrical ones becasue I happened to have some, the sort with two
pins and you bend them a bit to fit into the plate with two holes,
unlike the sram ones which have a pin and hole on each piece (ie
symmetrical.) The plate had cracked right through, still keeping the
chain joined but putting a bit of a kink in it.

I had three instances of that before the "magic" went out for me with
these links. This was with very few miles on them too. Powerlinks from
Sram have never, ever been any bother in tens of thousands of miles.

Robert