I attempted to have fixed by dealer and when they looked at it they told me 1) they couldn't hear it and somehow also 2) they fixed it.
When I got the car back, the headliner had been pried open on the left and right of the sunshade and, and, while not visible, you can tell the left side creased/folded when they tried to get access. If you touch the left side of the headliner, it makes a cracking sound now and gives easily.
I could have just broken my own headliner too, but I guess this is what I should expect when I take it to the dealer. I was also quite annoyed because I live an hour+ away and had called in 2 weeks prior to this appointment to order new tires (since the OEM ones failed to last 15K miles) and I had planned to drop my car off very early in the morning before having to catch a flight. We planned it all out, where I'd park, drop keys, etc. Morning of, I woke up at 430am, dropped my car on the way to the airport. At about 11am, hadn't heard anything, so I called the dealer to find they had not remembered about our plans. My car was still sitting on the side of the road. Then their tire tech called me to ask what tires I wanted again. They had failed to order them, and estimated another 2 weeks to get them in. So what should have been a tire replacement, headliner/sunroof rattle fix, and oil change left me with a broken'ish headliner that still rattles, an oil change, and no tires. I've since tried to make contact with the dealer GM who has ghosted me. I know we're all just people and these are just cars (not life/death) , but I'd expect a little more attention provided to a customer who has purchased and drives a new LX and LC500. Dealer confidence is at an all-time low right now for me.
@Oakleyguy are you saying it's the black accordion-looking piece that sits above the sliding mechanism of the glass on the sides?