On the first matter, splitting is a bit like duplication, you should expect to see most inspector attributes carried over into the new section (Snapshots are the main exception).
On the second, I can’t reproduce that myself. The command should disable itself if the conditions you’ve provided are impossible, so if it is lit up, it should work. I’ll need a more detailed checklist to understand where the problem is. To provide an example of that detail, here is what I tried:
Pressed Ctrl+N to create a new document in the binder.
In the editor, typed in the following text:
Placed the cusor at the end of “Line two”, and pressed Shift+Home to select it entirely.
Used the Alt+Shift+K shortcut to invoke the Documents ▸ Split ▸ with Selection as Title menu command. (In a second test, I also tried the contextual menu, as it seems that is what you are using.)
I should mention I’m on a slightly newer build than what you will have, so maybe if you follow that checklist and it doesn’t work, it was something that has already been fixed.
Hmm, still no luck. I set the auto-save idle timer up to 15 seconds to make it more difficult for save to trigger, but I was still able to get through this checklist. This is on a pretty vanilla setup, if you factory reset your settings does it make a difference?
Switched to defaults (and restarted Scrivener as requested) and that worked without the save first. Switched back to my settings (restarted Scrivener as requested) and it worked without the save first as well. Don’t know what happened with that first test that required a save.
FWIW, my auto-save idle timer time is 10 seconds.