Here is the use case:

- Set camera to custom mode, say C1 that has shutter speed 1/400 configured for it.

- While in C1 shoot as usual adjusting shutter speed as need, say to 1/125

- Let camera go to sleep

- Wake the camera up

Observe shutter speed is reset to 1/400

I'd expect this not to be the case because letting camera going to sleep and waking it up is not the same (shouldn't be) as turning it off and then on.

If you enable autoupdate for the custom settings it will keep updating it with whatever you choose duting shotting but this kind of defeats the purpose of the custom mode in my opinion, where you are guaranteed to always start from the same set of settings when switch to that mode.