If the horn beeps it is most likely the smart lock system thinks a door is still ajar, but if there is no horn beeping etc and the locks go up and down many times it is a fault with the actuators.
Take it to a Ford dealer and speak to them, if that dealer seems to be pissing in your pocket go to another.
The actuators are a well know fault with EF/EL's and Ford had many tries at fixing their **** up, they had many actuator revisions and changes in how the mangle behind the door trim to make slots for adjustment of the door actuators.
I haven't been doing them for over three years so maybe there is a sure fix from Ford be now.
As for the heat, they do have more a problem in the heat.
I can tell u one easy thing to test is, with a set of multigrips and a thick rag, pull out the door lock button out of the door, push the lock rod back down with the window down or u in the car with the doors closed, push the white plastic back inside the button as it would have popped half out when pulled off, now just push it back onto the lock rod.
This is done so that when the button is pushed down the button isn't sitting on the bottom, if it sits on the bottom and doesn't pop up straight away, it can when the temp rises and the plastic expands, making the lock come up and maybe cycle.