I don’t understand why it problematic to ask for v5 in the spec. The author of the generator of this feed clearly didn’t read the spec anyway, so whether it’s v4 or v5 wouldn’t have mattered. I’m sure there are tons of non-v5 guid tags out there and that’s ok by me.
I’d like it to at least look like a uuid though. Otherwise we will have to contend with what happens with the <guid> tag kitchen sink. My gut is this one is a length issue.