This is a very good question!
I’d suggest following @narthur’s helpful advice, or if you’re able, you could add a second data point on the same day. Then you’d go back to having that one-day buffer.
You used to have a buffer day because Beeminder has a fixed number-to-day data amount required.
If you made a goal that you “wanna do X daily”, and give yourself a day of buffer of 1 day, then at the end of the week, Beeminder is going to look for 6 data points as the minimum, or n-1 indefinitely until something is changed or modified.
So you’ll have 7 data points, and it’s smooth sailing and your graph will be in yellow, not red territory.
But if you miss a day, then at the end of the next week let’s say, you’ll only have 13 data points and that’s the bare minimum, n-1, aka a Beemergency.