My guess, they wanted both a keyboard and keyboard-less version, both looking similar hence the basis on the "Nokia U" design by community design they both seem to have.

Then they decided to scrap the original keyboard design, but they have a few thousand, so they wanted to, apparently, do a DDP with those.

Though, it kind of seems unlikely they'd make that many prototype devices so early on, but it's the only thing that fits with having both devices, but an early drop for developers (with a keyboard).