lec nonequivalent on bi-di IO Pad

Dear all,

Currently I'm doing the whole chip rtl to netlist LEC.
There are some noneqivalent points happen on bi-directional IO Pad.

The following is the noneq report message:

Compared points are: Non-equivalent
  (G) + 586   PO   /SDATA_0
  (R) + 586   PO   /SDATA_0

Compared points are: Non-equivalent
  (G) + 1198  BBOX /PAD_SDATA_0
  (R) + 1196  BBOX /PAD_SDATA_0
Due to these Non-equivalent points:
[INPUT]
  (G) + 11256 BUF  /PAD_SDATA_0/IO
  (R) + 8037  BUF  /PAD_SDATA_0/IO
 

 And the following is the diagnosis message:

1. Diagnosis for Non-equivalent key points:
  (G) + 575   PO   /SDATA_0
  (R) + 575   PO   /SDATA_0
There are extra unmapped key points in this logic cone
================================================================================
          ID     Type                Name
--------------------------------------------------------------------------------
   (G)   49     'PI(Z)'             /SDATA_0_z
   (R)   49     'PI(Z)'             /SDATA_0_z
================================================================================


The diagnosis point can be corrected by changing the following gates:
================================================================================
Correction             ID (R)     Type          Name
--------------------------------------------------------------------------------
DEL_INVERTER    8229      INV            /SDATA_0
FANIN_CHANGE   8230      MUX          /SDATA_0
change                 49          PI              /SDATA_0_z
to                         11406     INV           /SDATA_0  (G)
================================================================================

How to solve this kind of bi-di IO nonequivalent problem?

Another question is that I don't know why not all of the bi-di IO are reported nonequivalent.
Only several bi-di IO are reported.
If the bi-di IO noneq is a general problem, then all of the bi-di IO should be reported noneq.

Thank you!!