Let's say there cut is 2%.
If I sell a ticket for $50 list price to StubHub and then they sell it for $50 list price then they got 1 dollar from me and one dollar from the eventual buyer. That's $2 total.
If I sell a ticket to someone else on Stubhub for $50 then they also get $1 from me and $1 from the seller. The "double dipping" doesnt work out even before you factor in the overhead.
This is not to say they aren't manipulating market. Maybe they think they can make more money because humans are risk adverse and sell tickets for less than they should to optimize EV, or somethikng.
Thats why for example, if you work for Walmart you aren't allowed to buy walmart food for the team party and expense it. Expensing it is fine, but inflating the revenue figures by buying your own product is not.
In your second case, there was one sale at $50, meaning a $1 cut for the company.
This smells like an accounting trick to boost published revenue numbers, and seems plausible given that Stubhub announced they were on IPO track last year.
Case A:
Sale 1. Ticket holder sells to [shell company]: +$1 for Stubhub
Sale 2. [shell company] sells to ticket purchaser: +$1 for Stubhub
Case B:
Sale 1. Ticket holder sells to ticket purchaser: +$1 for Stubhub
It doesn't matter who the buyer or seller is, Stubhub says "This is a ticket sale so I will take a cut". Case A makes twice as much money for the parent company, and that's what's under suspicion in this thread, although there are other realistic reasons for the domain name behaviour seen by OP. And Case A makes assumptions about ticket pricing, e.g. if the shell company bought too many tickets and couldn't re-sell them all then whoops
In this case, StubHub could buy them and re-sell them to arbitrage the seller's price and the true market value.
Further, the shell companies could be something Stubhub is doing to derisk the arbitrage portion of the transaction to isolate losses associated with inability to sell the tickets for a profit to the shell company rather than to Stubhub.
Stubhub was supposed to IPO in 2022, but it doesn't look like they did. This kind of 'gaming the numbers to pump valuation' doesn't seem implausible for a company that is trying to IPO.