Plexamp not scrobbling tracks with Unknown Album

Hi, bit of a strange one. Plexamp (and Plex) works great, and scrobbles to Lastfm, except it won’t scrobble tracks with an Unknown Album. The Lastfm API definitely does allow you to, I wonder if it might be an issue with the AlbumArtist field? The logs look like the track is being scrobbled successfully, though I’m not sure why it looks like it’s been sent to trakt as well as lastfm?

Jun 23, 2021 17:24:40.303 [0x7f8a2a2b3700] DEBUG - Library item 30104 'Faith' got played by account 1!
Jun 23, 2021 17:24:40.308 [0x7f8a2a2b3700] DEBUG - MyPlex: Sending scrobble for account 1 for item 30104.
Jun 23, 2021 17:24:40.309 [0x7f8a2a2b3700] DEBUG - HTTP requesting PUT https://plex.tv/pms/:/scrobbles/publish?duration=175334&grandparentTitle=The%20Boy%20Least%20Likely%20To&guid=local%3A%2F%2F30104&index=7&metadataType=10&originalTitle=The%20Boy%20Least%20Likely%20To&parentTitle=Unknown%20Album&startPlayback=0&time=175334&title=Faith&auth_token=xxxxxxxxxxxxxxxxxxxx
Jun 23, 2021 17:24:40.432 [0x7f8a2a2b3700] DEBUG - HTTP 202 response from PUT https://plex.tv/pms/:/scrobbles/publish?duration=175334&grandparentTitle=The%20Boy%20Least%20Likely%20To&guid=local%3A%2F%2F30104&index=7&metadataType=10&originalTitle=The%20Boy%20Least%20Likely%20To&parentTitle=Unknown%20Album&startPlayback=0&time=175334&title=Faith&auth_token=xxxxxxxxxxxxxxxxxxxx
Jun 23, 2021 17:24:40.432 [0x7f8a2a2b3700] DEBUG - MyPlex: Scobbled with result 202
Jun 23, 2021 17:24:40.432 [0x7f8a2a2b3700] DEBUG - [Now] User is tomcopple (ID: 1)
Jun 23, 2021 17:24:40.433 [0x7f8a2a2b3700] DEBUG - [Now] Device is Chrome (Chrome).
Jun 23, 2021 17:24:40.433 [0x7f8a2a2b3700] DEBUG - [Now] Profile is Web
Jun 23, 2021 17:24:40.433 [0x7f8a2a2b3700] DEBUG - [Now] Updated play state for /library/metadata/30104.
Jun 23, 2021 17:24:40.436 [0x7f8a3e2b3700] DEBUG - Webhook: Delivering media.scrobble event by user tomcopple (1) to 1 hooks.
Jun 23, 2021 17:24:40.436 [0x7f8a2a2b3700] DEBUG - Statistics: (0s608m5ukf6rdk33xvvoopel) Reporting active playback in state 0 of type 10 (scrobble: 1) for account 1
Jun 23, 2021 17:24:40.439 [0x7f8a3e2b3700] DEBUG - HTTP requesting POST https://scrobblers.trakt.tv/plex/dbe9e5170dcc91db8547aa492f6739fc/ce3fca34d2b7e75fdb1ce86ddbad2613
Jun 23, 2021 17:24:40.440 [0x7f8a6eb87700] DEBUG - Completed: [81.159.84.4:57129] 200 GET /:/timeline?ratingKey=30104&key=%2Flibrary%2Fmetadata%2F30104&playbackTime=88981&playQueueItemID=33312&state=playing&hasMDE=1&context=library%3Ahub.home.music.recent&row=3&col=0&time=90000&duration=175000 (4 live) TLS GZIP 142ms 614 bytes (pipelined: 29)
Jun 23, 2021 17:24:40.714 [0x7f8a3e2b3700] DEBUG - HTTP 404 response from POST https://scrobblers.trakt.tv/plex/dbe9e5170dcc91db8547aa492f6739fc/ce3fca34d2b7e75fdb1ce86ddbad2613
Jun 23, 2021 17:24:40.715 [0x7f8a3e2b3700] WARN - Webhook: Error delivering payload to https://scrobblers.trakt.tv/plex/dbe9e5170dcc91db8547aa492f6739fc/ce3fca34d2b7e75fdb1ce86ddbad2613: 404

Nevermind, looks like it’s a lastfm issue, they just don’t accept scrobbles called Unknown Album.