LNK2001: unresolved external symbol XE 2015 in GENMOD

I recently upgraded from XE 2013 SP1 to XE 2015 (15.0.22) and with no changes to the code am getting LNK2001: unresolved external symbol errors from the Interface modules automatically generated by the compiler when using the -warn:all switch.

Hopefully attached is a code snippet showing the problem along with a batch file to compile with from the 64 bit command line.

The problem is relatively simple. My main program IPProc calls S/R AVERAGEIP

PROGRAM IPPROC
IMPLICIT NONE
CALL AVERAGEIP()
END

AVERAGEIP contains a S/R AVERMED which dimensions an array using a variable declared in AVERAGEIP

SUBROUTINE AVERAGEIP()
IMPLICIT NONE

INTEGER :: NRPTS

RETURN
CONTAINS
! even though this S/R is no longer called if I remove it the link error disapears
  SUBROUTINE AVERMED()
  REAL, DIMENSION(NRPTS) :: ZVEC
  ZVEC = 0
  RETURN
  END SUBROUTINE AVERMED
END SUBROUTINE AVERAGEIP

The integer NRPTS is local to AVERAGEIP yet when I compile with-check:all -debug:full -traceback -warn:all I get the following error

ipproc.obj : error LNK2001: unresolved external symbol AVERAGEIP__GENMOD_mp_NRPTS

Which does not make sense. NRPTS is noted in the object code for IPPROC which also does not make sense.

Can you please confirm this is a bug and not something I am doing and advise on a patch.

Cheers

Kim