I’ve repaired a few other pieces of equipment lately suffering from the ribbon cable dilemma as well as my Timefactor. so far Ive fixed a 16 x4 x2 Maci mixing console, Behringer mixer and a few other devices. I am a IT consultant and a certified PC repair Tech and I see this issue on PCs and Laptops too. I believe it’s from cheap ribbon cables. the cable itself is OK but the guillotine connector that gets crimped on to either end of the cable is the culprit. they are not very good Chinese made connectors. I changed the connecters to a Molex brand and the issue so far is permanently fixed. the issue I’ve seen is when the connectors are crimped on to the cable. the blade’s teeth that pierce the individual wires are not strong enough and give a little when being shoved through the wires insulation. I think either the PVC wire coating is to tough or the teeth are too weak.  after a bit of time, vibrations and heat it relaxes the contact points and lose their contact with the individual wires in the cable. by removing the cable and putting back or jostling it, for a bit remedies the problem.  wiggling the wire or pulling it off and on presses the teeth back into the wire. but to really fix it you need to change the ends to a good quality Molex ribbon cable connector. don’t be cheap buy the best one you can find.