Apple released iTunes 12.2 earlier this month on the same day it launched Apple Music. The new software was riddled with bugs, though, and users said iTunes Match was jumbling their music libraries, showing incorrect album art and more. That should all be fixed now.
Apple released iTunes 12.2.1 on Monday with fixes to various issues in iTunes 12.2. The update “fixes an issue for iTunes Match users where iTunes incorrectly changed some songs from Matched to Apple Music,” the update changelog said, noting that it also “provides a way to correct a library problem affecting iTunes Match subscribers.” It’s unclear if that solution requires a lot of legwork from the end user, however. Finally, iTunes 12.2.1 also fixes a “minor bug” and offers improvements for Beats 1.
You should find the update in the App Store now, or by opening iTunes and manually checking for updates.