Stubhub will sometimes adjust the listing price to make drive traffic and make the tickets appear more attractive to buyers. Fear not as you will be paid on the price that you list at not the price that it shows on the website.
Does StubHub still sometimes reduce the listed price below the price a seller has set?
Does this include increasing the active selling price vs the price i listed?
I've never seen them increase the selling price. They do charge fees to the buyer, but if you post at $400/ticket, they may drop the price to $380 (but pay you on $400), but I've never seen them, say, raise it to $420.