Intermittent Clutch Failure

Hyundai accent 2015 1.6 fluid manual. Brand new clutch and Master slave cylinder installed. The clutch has also been bled a couple of days ago however the issue still persists. When driving the vehicle for more that 30 to 40 minutes the clutch starts releasing slower and slower until it starts slipping totally and cannot find any gear.This also occurs in heavy traffic as well. One then has to push the vehicle over to the side then wait an hour or two then you are able to maybe find a few gears until it occurs again. Once the vehicle has been parked overnight then clutch feels normal again until the issue randomly occurs again. What could this be? Multiple mechanics are not able to help and have spent quite abit already on the vehicle. Any help will be much appreciated

 

Goch & Cooper Auto Services. These guys are Champions! They found the issue which was the Hydraulic pipe that was causing a build up of pressure, which in turn kept damaging both the master and slave cylinder. They found the issue by driving the vehicle until the issue occured which was at random times. Then stopped the vehicle when the issue started and began to work on the car wherever they broke down.