It appears the limit has been increased to 3 days with Plexamp 4.10.0. When downloading items, Plexamp will bring up a modal with a slider to determine the duration – if your playlist exceeds, the max duration to download is listed as 72 hours.
How did you try to remove items from the playlist?
From within the actual download item or on the playlist itself?
Removing items from playlists seems to work fine for me…
