Maybe it's a bug. Multiple browser windows.

[f1test]

Maybe it's a bug.

I load the program in the editor window. I run a program.
I open another browser session and set the page to Output mode.
I see the program running in the Output window.
I stop the execution of the program from the window in which I opened the editor. I load another program and run.
If I give a command in the Output window, an error is generated in ESP 32 and in the editor window. So the Output window sends commands to a program that is not its father.

[Electroguard]

It's not a bug, the Editor and Output pages link to the same script loaded in the Editor.
You can check the link by using the Run and Stop buttons in the Output page to control running of the script in the Editor page.

So if you load and run a different script in the Editor, you are breaking the link to whatever output was previously being sent to the Output page.
The error is because all the data vars and branch links from the Output page are no longer valid in the Editor page.