We're gonna have to disagree about that, I guess.
There are so many rules in D&D that, IMO, your character does what your character says it does. The number of exception-based combos that already exist makes it so that I HAVE to (as your DM, say) accept that what you tell me you can do, you can do. I can audit it later, sure. And I can say, "Nah, I'd like you to use Book X only (or this errata; or whatever).
Spiritual Weapon having concentration or not is significantly smaller a deal (to me) than a LOT of extant errata or splat-book subclasses, spells, or anything else that I haven't memorized the precise wording of. It'll be a table discussion like any of those. Assuming it even makes it into the game.