Anytime a circuit board trace gets hot enough to melt and cause an open there is a problem in that circuit...dead short or faulty component on that circuit or wiring harness issue, etc. They may have repaired the open circuit trace but fault has to be located to prevent a reoccurrence or additional issues in that circuit might occur.
Also, in the pictures you posted above it looks like the P24 connector has scorch marks on it near the capacitor. Wonder if that capacitor ever blew and was replaced earlier...?
Another observation, in post #16 above photo, the mounting standoff just above P24 looks a bit funky on circuit board like it got hot around the mounting screw that attaches standoff to circuit board. If you notice the standoff on the right, it attaches to the green sheet metal behind it and there is no annular paint relief where it attaches, however on the left one that looks like it may have gotten hot, there is what appears to be an annular paint relief where its mounted to sheet metal making me think that is an "intentional grounding point" with perhaps a star washer on opposite side. Anyway, it looks like perhaps something might have shorted through it to that ground point. But hard to tell from photos and no hands on examination.