A game on itch being updated much more rarely than on patreon isn't uncommon. I think I've seen cases where itch version was only a half of patreon's build or even less, so this case isn't that bad. Also, according to dev log, last update had both chapter 10 and 11, so it might be possible that it will be the same with the next one (12 and 13, maybe more). Would've been nice to have some info about Eva's plans for itch version of the game, though.