Not weird at all, "big day 1 patch" is very common for anything being distributed on consoles.
Is it common for the day 1 patch to rewrite the story?
Depends on the game, I guess. When it's an indie studio crunching to meet a publishing deadline, it's probably happened before.
I've read lots of comments from people bewildered that Hello Games is continuing to add features and work on bugs after the game has gone gold. Gold is the 1.0 release: they got the game to a state where there were no showstoppers, and now they're continuing to add value to the game, as well as address issues that only become obvious when large numbers of naive users (and their myriad hardware specifications) encounter a product.
Lol, Have a look at what Monkey Squad is doing with Kerbal Space Program. They added many game-altering and save-breaking "features", even migrated to a new version of unity, post-1.0 release. The days of distinctions between alpha, beta and release are gone. Developers are free to release most anything they want under whatever banner they choose.
This is what makes it a great age of gaming. All those one and done games are gathering electronic dust on my Steam shelf, yet Minecraft, Factorio, Starbound, Warframe, Space Engineers, 7 Days to Die, etc (all of those perma-early access games, pretty much) are racking up hundreds of hours over the year
I mean, Factorio with bob's mods can keep you going for a month
Didn't Starbound just leave Early Access?
An even better example would probably be Minecraft, which was released in 2011 and is still getting new features, biomes and blocks 5 years after hitting 1.0