Update: Alas, it has been confirmed as a technical error.
There's been no formal announcement from Penguin Random House, but lesen.net is reporting that they have numerous confirmations in their user forums that the change has been made.
Readers are reporting that the hard encryption DRM from Adobe has been replaced by a soft DRM, namely digital watermarks. Popular Random House titles like The Summer of blueberries and The Goldfinch are available as clean Epub files which can be downloaded, transferred, or converted with no hassle.
Digital watermarks are a type of DRM which does not lock down a file but instead adds extra bits of code which can be used to identify who bought the file, and where. This type of DRM is still uncommon in the US ebook market, but it is used widely in the "DRM-free" music sold by Amazon, Google, and Apple.
Digital watermarks are also growing increasingly popular among European publishers; as this infographic from Dutch ebook distributor CB Logistics shows, the majority of Dutch publishers have switched to this type of DRM. So have a number of other publishers in Europe.
At this time I cannot confirm the status of RH titles at Amazon.de, but I do know that at least one German ebook retailer, Libreka.de, is offering the ebooks with the new DRM. Lesen.net is still waiting for confirmation from Random House about the new policy, so at this time it is not possible to rule out an error or technical snafu.
If this is a new policy then it will be the tipping point. The trade ebook market will have made a transition from hard DRM to soft DRM similar to the one which music went through in 2007 when Amazon was the first retailer to sell mp3 files from 4 of the major record labels sans DRM.
Amazon was allowed to sell "DRM-free" mp3 files because the market was then dominated by Apple and iTunes. In a similar note, the German ebook retailer Libreka might have gained permission to change the DRM because Amazon dominates the trade ebook market.
I don't know if that is why Random House made their decision, but I can add that the new DRM-policy is at best confined to Europe. I just bought a couple Penguin Random House titles from Amazon.com and B&N, and both were encrypted with DRM, darnit.
But in spite of the presence of Adobe DRM, I still think the change in Germany was a test and not a technical snafu; it matches too closely with the rumblings I have heard from other major US trade publishers.
As you know, Macmillan switched the SF publisher Tor-Forge Books to DRM-free in the summer of 2012. They have shown no visible interest in expanding that policy to the rest of the company, but I know of other US publishers who are considering similar policies.
Thanks to embargoes I cannot tell you much in the way of details, but I do know of two different US publishers considering radical shifts in their DRM policies. One could be announcing that change next week, but at this point I don't have all of the details and cannot say for sure what will be announced.
You might want to go pop some more popcorn; the next month or so could be very interesting.