All of a sudden? during cruise speed? I think you would notice clutch in 2nd or third gear as you let off clutch. Clutch should be a gradual wear-out with chatter/hard shift/jerky. Not "all of a sudden" at cruise. Unless some kind of oil spill on it or broken link or spring.

Bottom line, truck needs more testing and examination. Not enough info yet. Try different clutch pedal release methods and see if you can induce slip or chatter without going overboard. Try to distinguish between bad clutch and motor not running right. Sometimes difficult. Tearing into clutch is the last resort.

Could even be due to gas cap not venting. Pulling a vacuum on the gas flow. Next time it does the "thing", jump out a take off gas cap and drive on.

Check motor oil for milky/weak coffee look/overfill. (your symptoms can be hydraulic lock)

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn