Some scripts seem to be breaking when re-loading a scene

In my project, there first scene plays an intro video. When the video finishes, it loads a new scene that contains my main menu. The menu is a worldspace UI with a camera that rotates between panels (settings, etc.). I also have a script that loads in PlayerPrefs at Start placed in the scene, which makes sure that all sliders/buttons are in the right position and applies volume settings and such that were set in the last session. This all works great.

However, once I press play to some into the game scene, then go through my pause menu and reload the main menu (via SceneManager), some things seem to be broken. I's using Coroutines to do the rotation smoothly, containing loops that rotate about 4 degrees at a time. When reloaded, the buttons that activate these only cause one step of the rotation, as if the loop isn't looping. In addition, the Start method that applies volume preferences doesn't seem to be running. The sliders are in the correct place, and if I click an apply button everything runs fine. I can post code or screens if necessary, but I don't know where to start looking. Any idea what could be causing it?