Apple and Sprint have offered enough phones at this point that one would think the two know enough about supply and demand. Though apparently that’s not the case, because Sprint is already issuing a warning to anyone who is preordering the 16GB and 32GB iPhone 5c units from its Web site today.

“We’ll do our best to get it to you by 9/20; but because of high demand, some phones will ship in up to 2 weeks,” Sprint explains. Apple and its carrier partners previously promised the the device, if ordered today September 13, would arrive on September 20. “iPhone 5c yellow 32GB will ship in up to 3 weeks,” the carrier said. It’s unclear if yellow was particularly popular during the past several hours, creating a shortage, or if there wasn’t enough units created in the first place.

So far we haven’t seen any other warnings from other carriers, though we’ll let you know if we do. Hopefully this is just a small issue that’s ironed out in the coming weeks. Sprint will also sell the iPhone 5s, though has not started to take orders for that device.