I'm unsure how long this has been the case since I only receive receipts when testing, but I noticed the receipt received on account creation for the initial payment does not actually show the amount charged, just the currency (USD in this case). See the attached screenshot for an example.
I can confirm this happens on the initial receipt, but I am unsure about follow-on receipts. I can also only confirm this is the case with Stripe, I'm unsure about the other gateways.
Note: Just FYI Stripe updated their API two weeks ago on 2014-03-13, but looking at the change logs nothing stands out to me that would cause this.