It’s called a cold solder joint. If the solder is porous or cracked like mentioned, it can cause intermittent contact. And not everyone will find it. An electronics person more likely than a mechanic.
A story again: Back in 1970 my dad had a new Plymouth and the radio was driving him nuts. It would work and then not work. The dealer had it out three times and never got it fixed. I was just back from basic training where I had a little electronic training but he wouldn’t let me mess with his new car. Finally in desperation he let me take the radio out and I just went over the solder joints, especially the ones that looked suspect, with the soldering iron. Radio fixed. Took less than an hour.