A couple of months ago the post office announced a degradation in service, that's what you're seeing. You should make sure to cancel your first donation check so that they don't double-dip you.

And yes, it has political cause. The republicans have been working towards destroying the post office for a couple of decades now. They passed a law forcing the PO to fully fund their pension plan, something that no other agency is required to do, and it eats a majority of their funding to no end. Why the dems haven't repealed that law when they are in office and in control of both houses, I do not know. They've had several opportunities.