I see what you mean, ECO mode does not function before entering and leaving the ALT mode.
Presumably this is due to the "disable screen off in alt mode" setting somehow.
Yes, I suspect LockMainPower/UnlockMainPower. If I set "Disable LCD off" to 'never', Canon power saving kicks in normally. I intentionally avoided telling about this setting in my previous post, because it can have a very confusing effect, especially on newbies (screen turns off while browsing the CHDK menu, etc.).
It's not clear to me why LockMainPower/UnlockMainPower is even executed at CHDK startup, and how it can cause this effect. We should fix this though, I only accidentally discovered that entering/exiting ALT cures the condition.
Does this occur on the g7x?