PID changed with and IOS upgrade

[wags]

We use various tools and scripts to watch the network to make sure things don't change "mysteriously" (aka nefariously).  Ran into something the other day that we cannot locate an answer for.

We upgrade IOS on a 3650 and a PID changed on the sh inv display.  It is a single device and the serial numbers did not change.   It is the PID for the stack, so maybe it changed because of a stack change in the past on the device, but we don't think so.  What ever the cause, we would like to know why, and understand how, the PID changed.  [WS-C3650-24PDM changed to WS-C3650-24PDM-S]  

sh ver

<snip> 

Switch Ports Model              SW Version        SW Image              Mode  
------ ----- -----              ----------        ----------            ----  
*    1 28    WS-C3650-24PDM     16.3.1            CAT3K_CAA-UNIVERSALK9 INSTALL

<snip>

sh inv
NAME: "c36xx Stack", DESCR: "c36xx Stack"
PID: WS-C3650-24PDM    , VID: V01  , SN: FDO2033V0C7

NAME: "Switch 1", DESCR: "WS-C3650-24PDM-S"
PID: WS-C3650-24PDM-S  , VID: V01  , SN: FDO2033V0C7

<snip>

sh ver

<snip> 

Switch Ports Model              SW Version        SW Image              Mode
------ ----- -----              ----------        ----------            ----
*    1 28    WS-C3650-24PDM     16.3.5b           CAT3K_CAA-UNIVERSALK9 INSTALL

<snip>

sh inv
NAME: "c36xx Stack", DESCR: "c36xx Stack"
PID: WS-C3650-24PDM-S  , VID: V01  , SN: FDO2033V0C7

NAME: "Switch 1", DESCR: "WS-C3650-24PDM-S"
PID: WS-C3650-24PDM-S  , VID: V01  , SN: FDO2033V0C7

<snip>

[Leo L · Accepted solution]

Raise a TAC Case.  This could be related to CSCvf67024. 

Please bear in mind that the affected appliance is a 9K, however, the codes are 16.X.X.