It seems that it has to do with the removed copy protection (you don't have to enter the right code at the door on the first (second) floor any more in order to open it, though you still can enter a code). See here: https://sourceforge.net/p/scummvm/bugs/4205
. Also the original version has it removed, but the issue doesn't occur there.
That's a shame, it may ruin the puzzles for those who never played the game before, they won't know they're missing part of the game. Gladly the original version (which is the one I like the most because it reminds me of the C64) doesn't have this issue.
It was an interesting find, thanks for mentioning it here. On the positive side of things, if someone wants to try the different endings, this can help making the game shorter. :)
Yes, those who play the game for the first time will be at least irritated. I've also once played the C-64 version as a kid. Politically correct or not, in both versions from GOG I miss the possibility to put the hamster into the microwave. (Sorry, I just found out that with certain characters like Razor - but not Dave - you can grill the hamster.)