Content that is available in the network "not found" depending in network key / node id
When trying to download a lot of blocks it turns out that occasionally a block fails deterministically. 
However, when trying to get that same block from a fluffy node started with a fresh network key (and thus new node id), it usually works.

So the failure seems to be NodeId related, pointing to potentially an issue in the lookup mechanism as the content is available on the network.


One such example is block body for block number `47830`, which is block hash ` 0x8a24f51c42f5c1e216351c6c2ab29d2ae25fc4f366ea690a4e13c640844412e7 `.

This results in a content id of: `0x345c7c1c31b50e20f6b320d0273690d89d0e2bc63a6d07b1b725e8b3ce5e819c`

We managed to retrieve this from node with id `0x3514da5e6fae802b62dbd381813a4fdd24d208f78506e10e7d94eaac0045354f` or from node with id `0x30c1ceb0ccc2448a674b73d573924743ce7622ae112b6fe74666fc01ca0cea4f`

It works when our node id is `0xb75e9ccdc42ce5191c754f0ad4aacebc17ffa822dd4613f46c12ba4993628f4c`, but e.g. not when our node id is `0x91239acd7248819228c893f3d10930b39a2a1ed7a999796a8845d47ebc9285b3`