Yes, there's exactly the same problem as with Freenet. Because same plaintext encrypts to same ciphertext there is huge problem with that. If I really don't anyone want to know that I got this data, that's failed scenario. It makes things easier for service provider, they don't want to know what they're storing. Just like Freenet's data cache. But if I know what I'm looking for, I can confirm if my cache contains that data or not. Therefore this approach doesn't remove need for pre-encrypting sensitive data. Otherwise it's easy to bust you for having the data.

Edit: GNUet quote:"The gnunet encryption scheme is remarkable in that it allows identical files encrypted under different keys to yield the same ciphertext, modulo a small block of metadata. These files can then be split into small blocks and distributed (and replicated if need be) across hosts in a gnunet system to balance load."

http://grothoff.org/christian/esed.pdf Efficient Sharing of Encrypted Data - Krista Bennett, Christian Grothoff, Tzvetan Horozov, Ioana Patrascu