I had the same thing happen on a 64GB card of mine. Rattles around inside like a pocket full of keys
I have to go and buy the Allen key set with the hole in the middle so I can open up the back and take it out. Not happy, not blaming yuneec or anyone, But, I've never had this happen with any other Micro SD card/slot. Still, its a learning process. I hope I don't damage the ST-16 when I do the open heart surgery to get the card out.
I'm sure I could take it to yuneec and have them do it, but I just want to get it done, So I will do it myself over the weekend.
I took my controller apart after loosing a card inside and before reassembly I added a small piece of thick double sided tape to the card holder body. When the ST16 is reassembled there is no longer a gap between the card holder and the ST16 housing. Hey, it's what worked for me. One of those spur of the moment ideas with limited resources.