It would seem that if the stablizer suffered damage in 1988 as the orginal post said, it would be known if it was from turbulence and not just thought to be. Also, why did damage occur the first time? Was the turbulence so great that it caused the damage, or was there an orginal manufacturing defect? If it was just due to turbulence, then you must be saying that turbulence encountered the day of the crash was much les than the orginal encounter, and the repair made it not capable of withstanding even this amount, otherwise it would make no difference whether it was repaired or a brand new one was installed.
You said it suffered delamination then, so it may have suffered delamination this time. Jetpilot your statement that it was a repair falt (though well it may be) is just speculation at this point. I don't know the cause yet, and neither do you.