Required to "Copy to Play Order" for my non-shuffled playlists

Hi. My playlists synced to my iPhone are in Album order. Beginning about a month ago, adding a new album to a playlist results in the album going to the bottom of the playlist on my iPhone. It's correct on iTunes, but wrong on the iPhone. The workaround is to right-click on the playlist and select "Copy to Play Order" before syncing.

I've been using playlist-based syncing two or three times a day since I bought my nano in 2006, and have never had to do this before; the "Copy to Play Order" command is supposed to only be required when you want to use the sequence of a shuffled playlist on iPhone or iPod.

The only thing that happened around the time the problem started was that I permanently turned off iTunes Match. Creating fresh playlists didn't correct the problem.

Please help!