Looks to me like that track had a problem, someone tried to fix it by gobbing solder over it, found the solder wouldn't bridge the gap until some of the tin had boiled out of it, so he delayed and destroyed the glue holding the track down to the PCB.

After 30+ years soldering for a living I could fix that in a jiffy. OTOH I can remember what it was like when I started so I feel your pain