What is this jumper wire on my A board?

[adgenet]

There is a wire jumpered near the amp on my CPS2 A board. Pictures of A boards I've seen online don't seem to have it.
Nothing looks to have been damaged and reworked / repaired on the board, so maybe it's factory? If it is, what does it accomplish, and why don't most boards have it?

 

[Anselmo]

I've seen it on a few A boards. I'm pretty sure it's from factory. Not sure what it does, but I think it has to do with the volume settings.

 

[adgenet]

Found this, but no other information anywhere on the internet it seems.
I wonder why this is only documented in passing in a single forum post and nowhere else.
Seems like important info to have.

That fix is only for early A boards. Later ones come with the fix already incorporated on the circuitry

It's meant to prevent glitches during power transitions. Glitches which
could corrupt the bigger toshiba chip (panel/buttons controller) RAM and
make it upload weird settings into the actual volume control chip (the
smaller toshiba chip).