Huh, weird. Archiving is working reliably for me, and I just tested full-text search against recently archived PDFs, and it too is working. Just a data point!
It's one of the annoying things about running (or being a customer of) a SAAS company, is that if something is wrong with someone's account, it can look like the whole world is broken --- but it might just be broken for some weird, unpredictable-but-deterministic subset of accounts.
(Or maybe it's only working for some weird, unpredictable-but-deterministic subset of accounts).
Good luck! I love Pinboard too.