Is it legal to use an older snapshot before the license was changed in accordance with the previous MIT license?
Generally courts are more holistic and look at intent, and understand that clerical errors happen. One exception to this is if a business claims it relied on the previous license and invested a bunch of resources as a result.
I believe the timing of commits is pretty important— it would be hard to claim your business made a substantial investment on a pre-announcement repo that was only MIT’ed for a few hours.
Licenses are important. If you are going to expose your code to the world, make sure it has the right license. If you publish your code with the wrong license, you shouldn't be allowed to take it back. Not for an organization of this size that is going to see a new repo cloned thousands of times upon release.
For the same reason you cannot publish a private corporate repo with an MIT license and then have other people claim in “good faith” to be using it.
All they need is to assert that the license was published in error, or that the person publishing it did not have the authority to publish it.
You can’t “magically” make a license stick by putting it in a repo, any more than putting a “name here” sticker on someone’s car and then claiming to own it.
The license file in the repo is simply the notice of the license.
It does not indicate a binding legal agreement.
You of course, can challenge it in court, and ianal, but I assure you, there is president in incorrectly labelled repos removing and changing their licenses.
Show me where they did this. All they have is a commit that says "Update License". An update doesn't imply a correction.
Stability's initial commit had an MIT license, so you can fork that commit and do whatever you want with it. It's MIT licensed.
Now, the tricky part here is that they committed a change to the license that changes it from MIT to proprietary, but they didn't change any code with it. That is definitely invalid, because they cannot license the exact same codebase with two different contradictory licenses. They can only license the changes made to the codebase after the license change. I wouldn't call it "illegal", but it wouldn't stand up in court if they tried to claim that the software is proprietary, because they already distributed it verbatim with an open license.
Why couldn't they? Of course they can. If you are the copyright owner, you can publish/sell your stuff under as many licenses as you like.