Olux Swamp Secret Not Working

So I'm trying to get all the secret discoveries, and I got stuck on the Lost Farmers one. I go around the house, after looking at the letters, and then walk up to the window. I inspect it and get told that it can break, but when I left-click on the window, the upper half only cracks a little. Am I doing something wrong or is it broken?

 

I've already reported this bug.
Hopefully it will be fixed soon.