Apple today released iTunes 12.4.3, a minor update that fixes a bug that could cause playlist changes made on iPhones or iPads to not appear in iTunes. Following the update, syncing should function as intended, with playlist changes showing up across all devices.
This update resolves an issue where playlist changes made on other devices may not appear in iTunes.
The new 12.4.3 update can be downloaded through the Software Update mechanism in the Mac App Store.
Today's iTunes update comes two weeks after an iTunes 12.4.2 update that fixed an issue causing playback issues when listening to Apple Music tracks shorter than 60 seconds.