Looks to me like the short side managed to source some stock to cover over the weekend.
My guess would be that they sat down with a bunch of the institutionals holding the stock, like Fideliy, Blackrock, etc, and they decided on a good price that will make the institutionals' quarterly reports look good without any risk, and the shorters and clearing houses will owe them one.
Also, looking at the institutional holdings, Fidelity alone holds like 20% total, including their funds , so I guess that's the reason they didn't need to restrict buying.