Hello brond,
Thanks for posting in the Apple Support Communities.
We understand the album artwork appears to be incorrect after syncing music to your iPhone directly from your MacBook, right?
If we have that correct, let's check if the songs are from the same artist or not that have the incorrect artwork. If you're seeing that the artists are the same, check the information of the song on your MacBook to see what's listed. If the information for the song is left blank, or aligns with another song information, then this could be related to what's occurring. Check out the following steps for assistance with checking the song information: Change song and CD information in Music on Mac - Apple Support
Change the name of the song, artist, or album
1. In the Music app 
on your Mac, click Songs in the sidebar on the left.
2. Select the item, then choose Song > Info.
If no information appears in the Info window, you can look up CD information in the Gracenote media database or send CD information to Gracenote. See If you don’t see songs in Music.
3. Type the new information, then press Return.
If the information is complete and correct for the song, let's check the Music preferences to see if artwork may be updating automatically. For assistance with the preferences, and more details on what each preference does, take a look at this resource: Change Advanced preferences in Music on Mac - Apple Support
Let us know if that helps to clear up what's happening. If not, confirm the steps you've tried already so we're aware of those. In addition, let us know if there are any similarities in the songs with the incorrect information.
Have a great day!
