You'll have to send me your save file, then, so I can take a look at it. There's no complicated code involved - a simple variable trigger - so something must have gotten seriously snarled up along the way if you're not getting the cave unlocked.
You can attach files to your messages, or you could send it to me via Discord, whichever you prefer. And send me the save file that is at the point you're stuck at - where you don't have the cave icon despite being at the point where it should be unlocked.
