Open Radar

 
Summary:
I have a bunch of smart playlists that I sync to two different iPhones. The playlists mostly screen out songs that have played recently. It always used to be, until iOS 10 and the iTunes version that accompanied it, that each time my iPhones synced, all that would transfer over would be the songs coming in to replace those that played. Now, I routinely see for an iPhone with over 600 songs synced via these playlists, that there’s a turnover of 570-590. I’ve started watching one smart playlist in particular, with 150 songs, that doesn’t even use the recently played criteria - it only removes songs when I’ve manually placed them on a different playlist - and seen that its entire contents have changed over during an iTunes session that involved multiple syncs of one of my iPhones.

Steps to Reproduce:
1. Sync several smart playlists to an iPhone
2. Wait a day
3. Sync the iPhone again

Expected Results:
Only a handful of songs sync over

Actual Results:
Almost the same total number of songs sync over again, although it’s not each time I sync

Regression:
This never happened from iPhone OS 1.0 through iOS 9

Notes:
It seems now like this is an iTunes problem, not an iOS problem, since it looks like the contents of the smart playlist are regenerating when they shouldn’t be