Well I can’t help much exactly, but I do hand write a lot of parsing code and "EOF" is a very old acronym convention that stands for an "End Of File" token. It’s sometimes thrown out as an "Unexpected EOF" error when the end of a file or input stream being read was met unexpectedly - i.e. the data being read was malformed or got chopped off early before it finished.
Here it probably means your network connection stream / socket got interrupted, but of course there could be 100 or more actual root causes of this (e.g. an invalid music file, or the handshaking between BlueOS / Qobuz is being done wrong). It’s NOT a specific enough error for good diagnostics, nor is it useful for the end user either. It could be a problem with either Qoboz or the BlueOS App. An "Unexpected EOF" generally counts as a bug that the software doesn’t handle this better. Sorry!
I have a Node 2i and though its software has gotten a lot better in the last few / several years, it’s still not terribly impressive. Very likely they messed up something with a recent update. Definitely frustrating.