Going through the new set, I found the following:
in Commanders Decks, there are a few cards with a modern frame:
- among the lands there is a card named ‘Urza’s Workshop’
- among White there is a card named ‘Disciples of Caelus Nin’
- among Red there is a card named ‘The Brother’s War’
- among Red there is a card named ‘Sardian Avenger’
- among Multicolor there is a card named ‘The Archimandrites’
- among Artifacts there is a card named ‘Staff of Titania’
- there are 2 green cards (those decks contains no Green)
I suspect none of these cards belong there, and it’s not just a case of the ’regular‘ (modern) graphics being used there, but I’m not sure since unreleased.
I found some additional issues with the BRC codes, that affects Scryfall, and consequently UrzaGatherer:
- Mind Stone is marked as a Common, but is Uncommon
- Azorius Signet is marked as an Uncommon but is Common
- Rakdos Signet is marked as an Uncommon but is Common
Of course it could be printing errors on the physical cards, but I doubt it.
I checked Scryfall, and it seems to be the additional 8 cards at the bottom of that section:
https://scryfall.com/sets/brc