Convert Object to Float Error

I widely deployed data field is working well. But one user is seeing something strange. The Data Field doesn't crash, it just doesn't execute a section of code. No ERA is produced. It just seems to skip some code. I don't try/catch anything. He just sent me the CIQ_LOG and it points to a line of code with this error:

   Error: Invalid Value
   Details: Cannot convert object to Float

That doesn't make sense to me. I added a print stmt to see what the value is. If it was a null, I think the error would be more clear. But otherwise a number should work. The line of code is using Math.round() which should handle any type of numeric value. Any ideas?