I posted this in the built in shipping category also, but then realized it probably belonged here.

All of a sudden, customers are seeing only First Class shipping rates (if a package falls within the weight limit for First Class). If it's heavier than that, they're not seeing USPS rates at all. I've had to take the site down for maintenance to avoid people choosing store pickup for everything. It's acting as though the First Class filter was on, but it is not and never has been.

I turned on debug, but the post office appears to be returning the rates for all the checked services. They just aren't being displayed to the customer.

Any ideas? I've had the site down for maintenance for hours now, and I have to get this fixed.