the hound plate itself wore out because of the friction of the shackle sliding back and forth.
We put plastic washers on the shackle "shaft" to keep the hound plate in the middle of the shaft and thus stop the chaffing.
Negative - that hound (Nacra / Inters) doesn't wear from friction. Even with spacers taking up all the slack, the hound opening will elongate just from the repeated cycle stress (waves, sheeting, etc). My F18 looks similar as well - neither are anywhere near failure but they are showing the same stress even with the spacers. The hound material is simply a little too thin to last a 'lifetime' and the hound will need to be replaced occasionally (at the first sign of cracking of the bottom weld).
I put the spacers in to A) keep the shackle from slipping over and pinching the spinnaker halyard leading to a jam or a chaffed spin halyard and B) eliminate a concern-provoking, "I'm 10 miles offshore and something sounds like it's going to break", POP/BANG as the shackle settles on every other jibe.