7i96S + 7i85S = 6 encoders?

Starting to commission a new build and am confused...

I've got a bare-bones config set up via mesact, just enough to start axis so I can see all pins in halshow.  All boards are recognized in mesaflash and halshow.
Hardware:

• 7i96S
  • sserial - 7i84D (mode 0)
  • Spindle encoder on TB2
    • appears as encoder.04 in halshow
    • also appears as encoder.05 in halshow
• 7i85S
  • sserial - 7i73
  • ENC0 - subspindle (quadrature signal from drive output)
    • appears as encoder.00 in halshow
  • ENC1 - V axis (quadrature signal from drive output)
    • appears as encoder.01 in halshow
  • ENC2 - X-axis linear scale
    • appears as encoder.02 in halshow
  • ENC3 - Z-axis linear scale
    • appears as encoder.03 in halshow

  Issue is that I can see 6 encoders in halshow, and encoder 5 appears to be a duplicate of encoder 4.  Counts & all pins are identical for 4 & 5 - i.e. they track together.

Anyone have a clue why #5 is showing up?  Something I did in HAL or INI?

Config files attached as zip, readhmid output attached as text file.
 

Yes, currently, the hm2 driver does not have the ability to use muxed 
( on the 7I85 for example ) and non muxed encoders ( on the 7I96S
for example) in the same firmware so the 7I96S encoder is configured
as a muxed encoder, but since it is not physically muxed, you end
up with an aliased encoder. Both encoder  4 and 5 are fully functional
and can even have different settings, but they read the same A,B,Z pins.

Thanks much PCW.  I'll simply ignore encoder.05 from now on.