I get the impression somehow that the version of Edna Breaks Out included here is cobbled together from the special edition German version and parts of the English dub of the original version but without being tested...

There's weird problems like the post credits title card not showing up when it's set to English. I thought it had crashed initially because there was nothing happening. When it's set to German it shows a title card and it makes a lot more sense. Not game breaking, but not promising.

While googling I came across someone who said they came across a puzzle that was broken and had to switch the game to German to pass that point...

Seems like Daedalic didn't test the English version to see if it actually works...

I had that too, although I think one ending worked and the other one did not. Right now I can't even remember if I ever got it to work by switching to german or did I just watch the credits on someone's YT walkthrough. Daedalic makes great games but they never really fix those few last bugs...

It doesn't show credits in either version, but it shows what happened to characters in "Harvey" ending. It doesn't show what happens to other characters in the other ending. However, like the OP said, the German version works without issues. Luckily I understand enough German that I could switch language to German and understand the jokes of the ending sequence. I don't know what's their thing with GOG. GOG version of Daedalic's "A New Beginning" has even more serious issues, (you can't save after certain point in the game) which Daedalic promised (in their own forum) to fix soon after it's release, but so far they haven't done anything to actually fix the issues. Instead they have published a new game in GOG. While I like their games (and I have bought most of those from GOG) I won't be buying their new titles unless they do something to make the previous GOG versions to work without issues.

PS: The menu puzzle is bugged, but if you do things in right order you don't have to switch to German.