Point, and they're experts at making this stuff so at best the result wouldn't be what they intended.It's not going to go bad or anything. But for strongly hopped beers, especially those with big late additions, you definitely benefit from drinking them fresh. Those forward-palate flavors and volatile aromas absolutely fade with age. Stone's got the right idea here.
As I understand it, their Enjoy By series uses the same recipe each time. So if you taste the 4/20 side by side with the 5/16, the difference you're observing is how much the hops fade in a month. And it can be a lot.
Do want to give the line another shot to see if I like it more this time though, preferably just as they hit shelves.