So the auto-updates are the intended way to download new versions, with the archives being just a way to get a minimal game that can then auto-update ?
That would explain the situation. I usually run games in containers, with no internet access - so of course the auto-updater failed. After running the game out of the container, it can download the update just fine.
As an aside, the update also downloaded a directory called SummonedByAccident-Public-dists, which contains two copies of the web version of the game, one of which is zipped, and the other not. Is this supposed to be in here ? This is an extra 1.2 GB that seem way out of place. A quick and dirty search through the game directory shows that this particular path is used only in the updater , and in a previous post (https://teamzorro.itch.io/sbarpg/devlog/950706/no-freebies), you mentioned having problems with file size limitations. That post was when the update that just became public was released to patreons. It looks like something went wrong with your build process at that moment, and we public edition freeloaders are only noticing it now.
And while writing all this, I just noticed that you uploaded the archive directly to itch. Well that was embarrassing. Please disregard the above, except the part about the weird copies of the game, that is still relevant.