Disc brakes click out and lose all tension, I am almost certain the cable is not slipping through. Can't find anything about this elsewhere. I would post a video, but I dont have the points to add a link.

What brand and model of brakes? Hydraulic or cable operated? What does "click out" mean?

They are Promax DSK-300R disc brakes. Cable operated, hard to describe without a video but when i pull on the brake lever there is a noticeable click noise and the cable tension is lost, the cable does not slip through the clamp bolt, rather the caliper on the disc brakes themselves moves.

Maybe the cable is caught, and clicks into place when the brakes are applied. Have a good look at the cable.

disconnect cable at caliper end, then pull the brake handle, check travel. Me, I would be using cable catch/stretch pliers as a holder for the cable while pulling the brake handle. Might be a broken component inside the brake handle persay, unseen...also, front or rear or both?

Check the caliper installation with the cable completely uninstalled. It should ideally be set up to be at close to the moving pad as possible without rubbing, and then the fixed pad brought in as close as possible without rubbing before attaching the cable. I like to get this alignment by removing the cable, loosening the fixed piston, inserting a business card between the moving pad and the caliper, loosening the caliper mounting bolts just enough that they move, then tightening the fixed piston until the caliper is stuck in place with the business card compressed between the moving pad and the rotor, then tightening the brake caliper bolts, which should set you up with close clearance to the moving pad and good alignment.

It may be that the cable housing is not fully seated in one or more cable stops.

thanks this was really helpful, not quite sure why it was clicking, but has since dissapeared.

Sounds reassuring...