Been like that for a while, at first I thought it was my browser or OS but then I tried it on other browsers under both Win10 and Linux Mint 20.3 all with the same effect. At first you could refresh the listing page and it would go to normal but now it acts like it's going to normal but pops back to the narrow left column BS.
You have to wonder if the bidder/buyer actually does pay for things that go to ridiculous amounts as eBay leaves the sold listings up even if the buyer backs out or doesn't pay. If the buyer does pay it could be someone with OPM (other people's money) such as stolen CC/debit or if they used their senile granny's checking to pay. Either that or it's some Saudi prince or someone else with unlimited funds.
I would ask who would pay that kind of money to just put the box on display when you could spin a replica box for under $300 but then I remember that there are people with lit glass display cases with keyboards in them.