On C12, I still experience 'sidechain' input is being gone, after disabl/enabling tracks

I used to have this issue back when I was using Cubase 10?

But I still have this issue, on Cubase 12 Pro mac.
So.

When I engage ‘sidechain’ on track A - frequency plugin.
Input is coming from track B.

And this happens when I, ‘disable’ track A + B both to save some CPU usage while I am mixing,
then after, when I re-enable those two tracks,

Sidechain is still being turned on with orange color,
‘BUT’ input is gone. Nothing is there. (I need to re-route input signal and choose from the list, this could get lost when I have multiple sidechaining going on)

I actually, thereby, write it all times on NotePad.

But, could this be just me… or well-known issue…?

Thanks!

Sorry for writing complaints, if it is just me, I will just figure something out.