My absolutely shot in the dark guess is that maybe strfry doesn't like tags that don't have single char (like, e or p or ..) as the first element in the tag array.. just a guess. Marketplace seems to have whole words as the first element. I don't see much else that would be tripping it up..
Discussion
Will prob do more testing later to see if this theory is correct .. been seeing this error a while, finally I'm on the case with an event that can cause it 😎
the spec only says that only single letter tags have to be *indexed* not that any such tags other than a-zA-Z are invalid
it isn't supposed to index these tags, and if the spec for marketplaces depends on non-single-alphabetical-letter tags then it is wrong
like this one:
https://github.com/nostr-protocol/nips/blob/d251ca0da5372ba0ae0df76754d96068266a6778/24.md
this "title" tag key is wrong, for example, i don't know why it isn't `T` that is the logical one to use for that
just to clarify, what the spec states about indexing means that you can't search for this tag using a filter