Agreed that it appears highly unusual, AA SLF, but do you have any suggestions?

I am considering the facts (I am assuming they are true) that: 1) the cockpit voice recorder has discussion about control problems, and has rattling noises, but no mention of explosion, etc.; 2) there were apparently no burn marks on the tail section.

I don't think that someone "loosened" the tail during maintenance. An "A" check doesn't include tail removal.