I've found that if you only spark one pixel of the E-Wall, it doesn't open. However, if you spark it two or more neighboring pixels, it does open up. Is that a glitch? Or is that intended behavior?
I think you're thinking of the wrong thing. I mean the thing that opens up when you spark it.
It's an actual problem with conductive walls since earlier versions.
This weird behaviour is best explained in the save linked below.
Turns out you just need to adjust the position of sparking conductor a bit to make it work.
Would be nice if it could be fixed somehow without breaking all the saves that use it as a "feature" :P