Java Expressions getNaValue()

Hi Experts,
Suppose we have a measure MeasX specified with navalue=0.
Also suppose we run mace -d <domain_path> -run -expression 'MeasX=2'

MeasX navalue is now 2:

$ printMeasure -d <domain_path> -m MeasX -specs
  Now executing printMeasure in domain '<domain_path>'.
  navalue                 :    2

  printMeasure completed successfully
$

Now, in a Java Expression, having either a DimensionalMeasure or a MeasureData instance for measure MeasX, the method getNaValue() always returns 0 (the initially specified navalue in the configuration).

Is this by design or may this be a bug?
RPAS Version 13.3.1.10

Thanks in advance,
Rui