Nothing immediately stands out as wrong, but it’s hard to tell without the data etc.
You should take a read of: Please read: make it easier to help you. It’s easier to help if you can provide a reproducible example that people can copy and paste into their REPL.
Debugging incorrect results can be difficult. See the suggestions in Debugging · JuMP
If it’s off by one for every instance, there’s likely a bug in your model. If it’s just wrong for this instance, then there’s likely a typo in the data that you’re using.