I don't think the battery pull itself is what does it though. You'll notice that when you pull a battery, when the screen turns back on, it was displaying the same thing it did before it turned off. This would mean the the lcd ram didn't get cleared. It would probably also mean that it's settings didn't get cleared either. That is probably the job of the OS to clear.

I couldn't find the spot in the OS where it happens, but I found it in the boot code. The boot code sends: 40h, 05h, 01h, 03h, 17h, 0Bh, and 0EFh. This makes me think that these aren't defaults. (13h-17h are undefined, but 13h-16h raise my contrast)

Also, not many people realize this because no one does it, but if you pull out the little battery as well as the AAA's. When you turn the calculator back on, the screen displays a bunch of garbage. Which makes me think that this is the only time that the lcd ram loses power. Maybe it will reset the screen flip settings too.

Add one more person with this interesting quirk to the list.  My old 84+ doesn't do this, but I just tested it on my new 84+se, and it works on there (no omnicalc ram restore, tho :'().
Serial: S-0306F (84+), P-0909M (84+se - a mysterious P factory calc!)