E70 X5 loose rear hatch latch—clamshell trunk door rattle and knock?

[X5Boise]

I’ve had a knock sound coming from the rear of the car for some time. It appears to be coming from either the top or bottom clam shell door when I go over some bumps, rough terrain, or when turning out of my driveway. Makes for an otherwise relatively quiet luxury car sound pretty cheap.

For fixes, based on a couple of internet suggestions:

• Felt-taped up the side unibody-attached plastic U-loops that the lower door will latch onto when closing (see picture). This seemed to have helped a little bit.
• Felt-tape (or electrical tape) the lower door latch. Just did it this AM—will try drive later today.
• Re-align the lower clamshell door as some E70 come misaligned from the factory (I haven’t tried this yet)
• Re-align the side body rubber bumper for the top door (I haven’t tried this yet either)

Also, after a further inspection, it appears that my latch on the bottom door, that one the top clam shell door closes on, seems a bit loose. I can wiggle it a little bit (especially the deep attachment point of the latch (the one that is towards the front of the car) and I suspect that is what is causing the rattle/knock sound. Is this latch supposed to moveable (made that way by design as it’s a “closing assist unit” BMW part 51247233909; appears to be a motor attached on the bottom) or is the attachment point defective?

https://www.ecstuning.com/b-genuine-...h/51247233909/

http://parts.bmwofsouthatlanta.com/s...ssembly=262304

http://www.realoem.com/bmw/enUS/show...diagId=41_1757

A prior suggested remedy was to wrap that latch with tape (electrical or felt) and this appears to tighten down the latch to quell down the noise---but if the latch has worn the joint at the rear, who knows when the front gives out and the top clamdoor will suddenly swing open?

If in fact the latch is supposed to be rigid and non-moveable, then it appears that I have a defective latch on my hands and will get it replaced (about $276 in parts as it comes as an assembly) or have a body shop weld it back (which appears to be a much cheaper option).

Thoughts?

Also a side note, here’s a rear lower door disassembly video to get out the rear hatch and/or need to take it apart to help tape down other parts for felt-taping (it’s in reverse order but gives a great idea of everything that needs to be taken apart).

https://www.youtube.com/watch?v=eiBeqc4ugr0