I had the same thing happen with, bizarrely, the same model of bass @Clarky, AVRI. Bought it on here, it played fine with lightish strings, sold it on here, buyer installed some La Bellas and off went the action, not to return no matter what. The truss rod didn't break, just appeared to be on strike. It went to a luthier IIRC and some form of dark art was performed bringing it back to it's former glory. Lesson learned, stay away from high tension strings on skinny necked basses.
As to your integrity and honesty old chap, never in doubt 👍