I’d definitely open the super and check how capped they are. My bees keep moving the nectar/honey around in the cells at the end of the frames even when the majority of the frames are capped. I wouldn’t take it as certain that because you’ve seen a drop in the end cells that the bees are emptying out the super.
What have you got below the super? Is there much honey below, have they got space to move the honey down?
A good indication of what they are doing from the end is the interface of the nectar/honey with the air. It’s to do with viscosity and surface tension. In your top photo you’ll notice that in many of the frames the interface is almost vertical - this will be honey. The lower picture looks almost all to be nectar in comparison.