The original artist was uncomfortable with the increasingly explicit nature of the game and wanted to stop, so the dev let him, and they found a new artist. This isn't a "patreon scammer" type thing, this is a "indie projects tend to hit bumps that change the whole project", which is why you see projects get derailed on Patreon all the time, as Patreon is where devs with no support go to get supporters.
But still, its kinda stupid strategy, and this is why so many devs abandoned their games, cuz sometime they dragged their development cycle to get more money, and then from time to time, they lose their patron to the point the money they get monthly from patreon, cant support their next updates budget, this is what we called milking and can be considered as a crime of fraud (Cuz their patron support them to finished their game and get full games in the future, but instead they betrayed their patron and abandoned their game) .
And the problem with this Dev, is that she choose to rework the game from the beginning again, when they can just replaced all of the old arts, and tweaks the story a little bit so it can catch up to the old version and give her patron a "Fully fresh/new" Contents, cuz all those 5 chapter story its not that deep into the main story yet, and can literally add so many things using that previous story as a foundation and this dev also choose to release chapter 5 in the past when the old artist already said he wants to quit and copyrighted all his art in old version of the game (He is asshole for sure for doing that, no doubt about it), i mean, she can just scrap the project the moment the old artist wants to quit, and start the reworks right there, instead, she choose to released that useless chapter 5 and wasted so many months of development cycles because of that.
She also said that the new version of chapter 5 supposed to be released around august this years, which is not happening, so yeah, being indie developer doesnt mean they cant do that milking stuff, instead they are the ones who probably do that milking stuff more often than other type of dev out there, and based on how this dev do all her works, theres so much reason for people here calling her out for milking her games.