Measurement Price Calculator – srcond value problem

Hello!

I created a Loom video demonstrating the issue. When I enter a number in the first field, that number also appears in the second field. Even if I delete it, it reappears. What can I do to fix this?
https://www.loom.com/share/5b54088c529a4fa6aebb0fcd6729a98e?sid=4fb6faf6-e7d6-400c-8fe0-00ab56628651
Thank you

The page I need help with: [log in to see the link]