The ones I’ve seen are not cold solder. The upper board pad was not pre-tinned at all so the only solder that existed was the pre-tin on the component. This is a no-no for reflow soldering. Not enough solder on the connection, so it fails mechanically.
Note also that dull looking solder joints are quite normal for lead-free solder used nowdays. They should be shiny, chrome looking for lead type solder, but may not be for lead-free.
