I was lucky enough to get a TA ticket for the three games. I'd imagine the ones that are on sale aren't TA ripping each other off but more likely, as someone mentioned, tickets from Croatian fans or even more likely, "fans" who have been given sponsors tickets. Anyone that's been to either of the two Scotland games would notice the majority of jeans & jackets guys. It's not their fault, it's the way UEFA/FIFA functions.
When I bought my tickets I took the option to buy physical tickets for an additional €5 a go. They're selling for stupid money on eBay but that should settle down and end up much cheaper.
Mon the Scotland! 😄