Some have already been mentioned.
But others would be omissions, spelling errors, and personnel errors (and combinations of all three).
- associating John Smith with John Smith instead of John Smith.
- calling John Smith, John Smit - and giving John Smit his own page because of their own error.
- My personnel favorite is when they give John Smith a page, and John Q Smith a page even though they are the same person.
That is why some artists have multiple AM links on their MB page - because they have minor spelling differences.
And that is why some of the AM pages aren’t listed on MB - the credits listed are for multiple artists with the same name.
They list Pedal Steel Guitar as Steel Guitar.
They call all bass guitars as bass guitar - sometimes you may find a double bass.
Do they list Coronet and French Horn, or is it classified as a Trumpet and Horn? (been a while since I checked)
Like I said in my first post - most people don’t know the difference between a those instruments and all of their variations, so it is fine for them. But if you want any legitimacy, one would want to differentiate.