As long as it posts before your next statement cycle, you should not be considered 30 days late. I can't speak for sure about your bank, but I worked at two different banks and the concept of 30 days, 60 days, etc. always applied to months. When you miss your first payment you are in the first delinquency bucket, which is 1+ days delinquent. When you miss your second payment, you move to the second delinquency bucket, which is often referred to as 30+ days delinquent.
Since you paid before you cycled for the second time, you should be back to current on the 31st, but have a payment due the next day for June.