"stack-mac persistent timer 0" does not appear in running config?

[RB6502]

I have a pair of C9500 switches running IOS-XE 16.12.04.  The output of the "show switch" command shows
"Mac persistency wait time: Indefinite".  However, when I search the config for the "stack-mac persistent timer 0" command, I do not see it.  My understanding is that this command is not a default, so is the command missing from the config a cosmetic, did the default change to enabled, or something else?  

[MHM Cisco World]

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvy11550

check this bug

[Leo Laohoo]

Upgrade the firmware of the stack or monitor the CPU &/or Memory control-plane or risk losing them due to a memory leak.  

16.12.X, particularly 16.12.4, is extremely buggy.

Don't believe me?  Have a look at below: 

The above is the control-plane memory of a standalone 9500 on 16.12.4.  The red box highlights is the time when the QuoVadis certificate issue (FN - 72323 - Cisco IOS XE Software: QuoVadis Root CA 2 Decommission Might Affect Smart Licensing, Smart Call Home, and Other Functionality) is happening.  

The control-plane memory of the 9500 should be between 25% to 30%.  Anything higher than 35% means there is a memory leak.  

[Reza Sharifi]

"Indefinite" means no timer is configured or 0, and you are using the local Mac address. So, if you want to see the actual second(s) configured, try a different number between 1-60. That should also appear in "sh run" in addition to the "show switch" output.

HTH