Unchecked albums added to iPhone when syncing from iMac

I selected Albums (only), but unchecked albums are added to my iPhone.

I have an iPhone 6s which I want to use as a music player. My Music collection on my iMac is mostly ripped from my CD collection.

I am manually Synching music from the iMac to the iPhone. I do not have any checks under the Artist tab. I have selected the Albums I want to synch to the phone, but several/many albums which are not checked have been synched to the phone. Why? And how can I prevent unchecked albums?