Hello, looking for some advice here on my 15 F-150 with the 3.5, truck states it’s overheating but mechanical shop says it is not doing it.

Couple of things have been replaced on it already as well, which includes:
water pump
thermostat ( multiple times )
cylinder head temp sensor.
it has been block tested and not the issue.

it’s only doing it when your at a speed of 40-60 for a few miles. Anything below it or above it, it doesn’t do it. Let me know what your thinking!