If that cable is anything like laptop keyboard ribbons, then it's not the cable that's faulty, but the plastic connector that's missing a locking mechanism.
Edit: Here's an example of Sony's keyboard ribbon and plastic connector with the retainer lock
maybe a shim of some kind as long as you're not blocking the circuit. Use plastic or wood of course..
I hate to be responsible for giving bad advice, but if you think it's safe, you might also want to glue the shim in with non-conductive adhesive if it's going to be permanent so it doesn't fall out.