The Haversine formula is one of the most complicated things I’ve set up in Thunkable. It’s not surprising you’re having problems with it.
Have you tried debugging each value? I use this method: Debugging in Thunkable X (Video)
If that doesn’t find the cause for you, would you be able to share a link to your project? You’re welcome to send it in a private message. It’s easier for me to troubleshoot it with the blocks rather than just the screenshot (although that is helpful!).
Also, see this response I provided and the link I included in the post: Location sensor for tracking distance - #6 by tatiang