Basically the solder job looks very questionable. The whole joint has come loose which wouldn't be possible if it was actually soldered correctly. This means that it was applied to some surface where the solder doesn't wet for whatever reason - maybe it isn't metal, maybe it's enamelled or covered with lacquer etc. Or maybe it's just a classic cold joint.
If there's meant to be an electrical connection there, then the only option is soldering. Or in case these only serve as mechanical strain relief and the soldering was merely some sort of "poor man's glue", then you could replace them with actual glue.
But if they have to be soldered, there must be a proper metal surface on both sides where you can actually solder something. If so, then you should re-do these joints. Remove them with a solder wick copper braid, clean up, add flux, solder anew.
Now the real question is if any of the metal traces inside the FFC are damaged - repairing those in a professional way is more or less impossible. I'd replace the whole cable in that case.