Large amount of skipped scrobbles on Spotify import

[sre3]

I recently imported ~72k scrobbles from spotify. After importing, majola outputted:

Successfully imported 72734 scrobbles 
Skipped 45340 scrobbles 

Looking at the logic in import_scrobbles.py and parse_spotify_lite, it seems to skip when songs are played less than 30 seconds, however, I also have a last.fm account (has less data, so I imported from spotify) with most of my sources set to scrobble after 50% playtime, which is probably about ~1.5mins for the average song I listen to. Majola imported less scrobbles compared to last.fm consistently, with specific artists seemingly losing half of their scrobbles... I looked in the logs, but there was nothing related to the import. Is there a way to see why the scrobbles were skipped?