I hope this will attach the screen shot.
I think the solder paste applied to the joint maybe less than enough or the pad maybe too small. There seems to be 4 pads on the key itself. 2 in the front for attaching the key to PCB and 2 in the back for contact trace. If you can see the photo attached, the key is lifted from the PCB in the front, indicating that the solder pad in the front is not holding the key in place. This is very hard is line QC to find even with AOI (automatic optical inspection).
I can try to ask help from friend to get access to microscope and soldering station here (in silicon valley). And if the information is available, maybe I can get it fixed and work.