Hi Jeremy,
Maybe this information is helpful to solve this bug — recently I was editing the main.js file for a project and faced the same problem that the changes were not immediately reflecting in the experiment. I made a copy but soon the problem started showing with the new copy (and a copy of the copy) as well. The code especially had problems in updating when I copy-pasted a couple of lines from elsewhere (instead of editing directly).
Best,
Umesh.