What are you doing to me Google? This is the first time I’ve ever seen this problem, but my segments are not working in my reports for the month of April. Not just my custom segments, but the generic segments such as non-paid search traffic.
What are you doing Google? I have other ways to pull the data down, but this just wastes my analysis time.
Now I know that this isn’t due to sampling as this site doesn’t have over 500,000 visits per month, but what else could it be? Stay tuned while I find an answer!

The Google Analytics have now acknowledged on their blog that the missing April data is a fault and they’re working on a solution. The estimated time for the fix to be ready is May 23. Over 10 days away.