Why aren't my health bars updating correctly on other layouts?

Here's my project file, health bar logic is in the "eCharacters" event sheet: ufile.io/dwc1s

If you take damage in the Main layout, the health bar updates normally, changing size based on HP lost. But if you go to FirstTown or NextTown, the health bar doesn't update if you take damage.

I can't think of any reason why this would happen, since all layouts share the same event sheet.

isPlayer variable is set to false on the town layouts.