The reason why the dream segments soft-lock you currently is because a third option "Sleep without a Dream" doesn't get displayed.
I don't know why that option doesn't show up on existing save files considering that its presence is unconditional.
I test every build on a completely new save file and it should work, but we do not have a cheat menu to allow you to recoup any progress you lost, sorry.
We are going to rework the existing days 5 - 8, so existing save files will get broken again.
The way the save file system currently works is that it dumps the current RAM into the save file. As a side-effect, this means that it remembers the code as it was in the prior version... which isn't a problem if it doesn't change, however, if it does change, that is where unpredictable bugs can happen.
It's the default saving system from Godot, and I am planning to write our own save handler, change the way the game tracks progress in order to make it agnostic to the build version.
But that will take some time to come out, so I cannot offer a quick fix, unfortunately.