Yeah, unfortunately this is a bug that hasn't been fixed for awhile now. There used to be a lot more game breaking bugs involved with loading saves, making it borderline impossible to play; but those have since been ironed out
What I recommend is saving only AFTER you buy the blender, which luckily doesn't take too long. All the doors being unlocked, while very much a bug, isn't game breaking. It does make progressing in the quest pointless though lol.