Yep. That’s by design.
I think the lenience started out because it’s usually on a Saturday that you wish you’d enabled weekends off, but that’s within the akrasia horizon for the next weekend, which means that you couldn’t schedule it to start until two weeks out, which really sucks.
Or imagine creating a new goal mid-week, deciding that it’s a weekday-only goal, but not being able to make that be true yet.
For simplicity and sanity, we eliminated the usual constraint. Shout if you find yourself tempted to abuse this feature.