If I used on old version of the process it works well.
The difference between the process is that after the migration to 8.0.1 SP3 to 8.2, all my xfaform variable in all process appears in red in the xpath builder with the Error:java.lang.reflect.Invocation.TargetException.
The process well worked for all that. In some cases clicking "reload schema from file" solves the problem, in other I just needed rebounding the schema to the file before.
I did that for all the process with no issue except for this one.
If I don't touch the variable the process well works but if fix the variable the process doesn't work anymore.