Calling this phenomenon "Gatecrash"... Bravo for that. :D
We fixed it. Should be better in the upcoming release.
Just for fun, some hints about the code branch we missed: If a typical standard deck wants 24 lands and you have 10 non-basics, how many basics should you add to fill out your land count? Okay, now do that math for 25 non-basics. ;) Little bit of a facepalm, but it was easy to fix.