No, it isn't supposed to be like that. I've experienced that issue a few times too in other mods and I have no idea what causes it. If you open the mod in notepad you will see it is set to -30, there is definitely something strange going on with the client here.

What's the weirdest to me is how the game somehow overwrites ONLY the gravity settings while keeping everything else as it should. Perhaps a leftover from when custom gravity wasn't a thing.