If we have a schema with newVariableInstance that uses a non-constant DFDL expression for the default value, that default value is never set. For example:
When the inputValueCalc expressoin is evaluated, we fail with the error
According to the spec:
So we are likely just missing the logic to evaluate and set the default when when we create the new VariableInstacne.
This might also affect dfdl:defineVariable as well, which is allowed to also have expressions as the defaultValue, as long as the expression doesn't reference the infoset and only other variables.