I believe this is because you have to complete the loop with the loop node. It wont ever proc the done branch because it could not complete the loop.
I am unsure if done branch to same route is accurate, but you have to at least connect the end http request back to the beginning of the Loop Over Items node. Like this:
The Loop node receives input, but he doesn’t create output for the edit field node to execute. I’ve uploaded screenshots of the Split out, the Loop node & the test workflow to show that the workflow stops at Loop Over. I hope that helps.